You searched for subject:(bedform).
Showing records 1 – 20 of
20 total matches.
No search limiters apply to these results.
University of Waterloo
1.
Obach, Lana M.
The Hydrodynamics of Pool-Riffle Sequences with Changing Bedform Length.
Degree: 2011, University of Waterloo
URL: http://hdl.handle.net/10012/6111 
► Previous research has demonstrated that pool-riffle bedforms play a critical role in channel stability and ecosystem health in many natural gravel-bed channels. Although the bedform…
(more)
▼ Previous research has demonstrated that pool-riffle bedforms play a critical role in channel stability and ecosystem health in many natural gravel-bed channels. Although the bedform length is known to scale with channel width, no experimental research has yet isolated the effect of bedform length on pool-riffle hydrodynamics. To improve the understanding of the hydrodynamics of these bedforms so that they can be better incorporated in restoration practices, flume experiments were conducted testing the flow at seven different bedform lengths.
Velocity profiles are measured in a 17 m flume with movable PVC bedforms using ultrasonic velocity profilers (UVPs). Smooth two-dimensional (no sinuosity) bedforms are used in order to isolate the key dynamics in convective acceleration and deceleration. The angle of transition between pool and riffle heights was 7°, so that permanent flow separation did not occur. Parameters calculated from the velocity and turbulence profiles include the Coles’ wake parameter (a measure of the deviation from the log law), shear stress estimated from the velocity profile, shear stress estimated from the Reynolds shear stress, and vertical velocity. From the individual velocity time series, the integral length scale and the integral time scales are also calculated.
Overall, the length of riffles and pools exert a fundamental control on the distribution of flow and turbulence within a channel. In the pool, energy is dissipated both through turbulence and as the flow is redistributed to uniform flow conditions. In the riffle, kinetic energy increases as the flow velocity increases, and as the length increases, the flow moves towards a new uniform flow condition. The results start to explain the reasons behind the persistent scaling relation between width and bedform length. It can be concluded that uniform flow conditions exist at the end of the pool when the bedform length ratio is greater than approximately 1:5.0 when the riffle length is held constant, and that uniform flow conditions are no longer observed at the end of the pool when the bedform length ratio exceeds 1:7.0 when the pool length is held constant.
Future research should concentrate on extending the results to include three-dimensional pool-riffle configurations, repeating bedform configurations, internal scaling parameters, and sediment transport. Ultimately, as the hydrodynamics of pool-riffle sequences are better understood, better bedform designs can be implemented in restoration projects.
Subjects/Keywords: Pool-riffle hydrodynamics; bedform maintenance
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Obach, L. M. (2011). The Hydrodynamics of Pool-Riffle Sequences with Changing Bedform Length. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/6111
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Obach, Lana M. “The Hydrodynamics of Pool-Riffle Sequences with Changing Bedform Length.” 2011. Thesis, University of Waterloo. Accessed January 21, 2021.
http://hdl.handle.net/10012/6111.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Obach, Lana M. “The Hydrodynamics of Pool-Riffle Sequences with Changing Bedform Length.” 2011. Web. 21 Jan 2021.
Vancouver:
Obach LM. The Hydrodynamics of Pool-Riffle Sequences with Changing Bedform Length. [Internet] [Thesis]. University of Waterloo; 2011. [cited 2021 Jan 21].
Available from: http://hdl.handle.net/10012/6111.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Obach LM. The Hydrodynamics of Pool-Riffle Sequences with Changing Bedform Length. [Thesis]. University of Waterloo; 2011. Available from: http://hdl.handle.net/10012/6111
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Illinois – Urbana-Champaign
2.
Perillo, Mauricio.
Flow, sediment transport and bedforms under combined flows.
Degree: PhD, 1655, 2013, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/44484
► Combined flow, which refers to a combination of unidirectional and wave-induced oscillatory flows, is omnipresent in natural environments and generates a range of bedforms on…
(more)
▼ Combined flow, which refers to a combination of unidirectional and wave-induced oscillatory flows, is omnipresent in natural environments and generates a range of bedforms on sandy beds. Combined-flow bedforms are abundant in coastal and lacustrine environments, as well as in their ancient counterparts in the rock record. However, few experimental studies have focused on the relationship between the morphology and formative hydraulic conditions of combined-flow bedforms. There is thus a wide range of unexplored stability conditions for such bedforms, especially with intermediate oscillation periods. The aim of this research is to undertake new experimental work in the Large Oscillatory Water-Sediment Tunnel (LOWST) in order to address this gap in knowledge. The LOWST has a test section 12.5 m long, 0.8 m wide and 1.2 m high, with the oscillatory motion generated by three pistons. Unidirectional currents were superimposed on these water oscillations using two centrifugal pumps. Fifty-five experiments were conducted in the LOWST, both with and without an initially flattened bed.
Bedform development in a 0.25 mm diameter sand bed was studied under pure oscillatory and combined flow conditions with oscillation periods of 4, 5 and 6 s. The maximum orbital velocity (Uo) was varied from 0.10 to 0.70 m/s while the unidirectional component (Uu) was varied from 0 to 0.50 m/s.
This thesis presents new experimental data on
bedform initiation and development under unidirectional, oscillatory and, more extensively, under combined flows. In particular, this study was able to populate zones of the Terra incognita region previously defined in the literature (Southard, 1991). In this thesis, the stable
bedform configurations under a diverse range of flow conditions were studied and divided into no motion (NM), 2D symmetric ripples (SR), 3D symmetric ripples (SR), 3D symmetric dunes (SR), 3D asymmetric ripples (AR), 3D quasi-asymmetric ripples (QAR), 3D asymmetric dunes (AD), 3D current ripples (CR), 3D current dunes (CD) and upper-stage plane bed (USPB). Each of these
bedform stages was described, characterized and reproduced in dimensional and dimensionless phase diagrams. A complete re-evaluation of the nomenclature for combined flow bedforms is proposed, which includes their planform and the cross-sectional geometries in order to better represent the bed morphologies. This new nomenclature was carefully selected in order to integrate the
bedform studies both in the unidirectional and oscillatory literature. One of the main changes that allows the integration with the nomenclature used in unidirectional flows is the reclassification of large ripples as dunes. Furthermore, the introduction of the planform and cross-sectional geometries as properties to classify bedforms leads to the definition of a stable phase space for two-dimensional symmetrical ripples and three-dimensional quasi-asymmetrical ripples. Furthermore, the experimental data collected under unidirectional flows larger than 0.30 m/s allows expansion of the current…
Advisors/Committee Members: Best, James L. (advisor), Best, James L. (Committee Chair), Garcia, Marcelo H. (committee member), Parker, Gary (committee member), Baas, Jaco H. (committee member).
Subjects/Keywords: Bedforms; Combined Flows; Wave-Current Interactions; Phase diagrams; rippes; dunes; bed morphology; bedform development; bedform genesis
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Perillo, M. (2013). Flow, sediment transport and bedforms under combined flows. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/44484
Chicago Manual of Style (16th Edition):
Perillo, Mauricio. “Flow, sediment transport and bedforms under combined flows.” 2013. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 21, 2021.
http://hdl.handle.net/2142/44484.
MLA Handbook (7th Edition):
Perillo, Mauricio. “Flow, sediment transport and bedforms under combined flows.” 2013. Web. 21 Jan 2021.
Vancouver:
Perillo M. Flow, sediment transport and bedforms under combined flows. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Jan 21].
Available from: http://hdl.handle.net/2142/44484.
Council of Science Editors:
Perillo M. Flow, sediment transport and bedforms under combined flows. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/44484
Universiteit Utrecht
3.
Mulder, Joost.
Upper flow regime bedform stability - Cyclic steps, their geometry and position in a bedform stability diagram.
Degree: 2010, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/40967
► Cyclic steps are upstream migrating bedforms of the upper flow regime, associated with slopes. They are characterized by trains of hydraulic jumps. Upstream of the…
(more)
▼ Cyclic steps are upstream migrating bedforms of the upper flow regime, associated with slopes. They are characterized by trains of hydraulic jumps. Upstream of the hydraulic jump the flow is supercritical and the bed erodes, while downstream of the hydraulic jump the flow is subcritical and deposition takes place, resulting in an upstream migration of the
bedform and the hydraulic jump. The formation of cyclic steps is empirically researched doing experiments using a tilting flume. Chute and Pools are described by Fukuaka et al. as a limiting case of cyclic steps for which the steepest bed slope realized just upstream of the hydraulic jump is still rather mild. Here, the definition of cyclic steps is discussed and a suggestion is made to use the term cyclic steps with the additional information of the state of the hydraulic jump, which can be ‘normal’ or ‘submerged’. The sensitivity of the cyclic step geometry is analyzed by the median sediment grain size and flow characteristics. The geometry of the cyclic step can be described by the length, the height, the slope and the position of the highest point. Per geometry characteristic the following parameters are tested: the flow specific discharge, the flow sediment volume concentration, the median sediment grain size, the average Froude number, the mobility parameter, the streampower, and the relative flow depth. This resulted in two functions using the streampower to obtain the cyclic step’s length and height. Based on the experiments, a
bedform stability diagram is created for the upper flow regime using streampower and slope to plot upper plane bed, antidunes, cyclic steps with a normal and with a submerged hydraulic jump.
Advisors/Committee Members: Postma, G., Cartigny, M..
Subjects/Keywords: Geowetenschappen; Upper flow regime, bedform stability, cyclic steps
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Mulder, J. (2010). Upper flow regime bedform stability - Cyclic steps, their geometry and position in a bedform stability diagram. (Masters Thesis). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/40967
Chicago Manual of Style (16th Edition):
Mulder, Joost. “Upper flow regime bedform stability - Cyclic steps, their geometry and position in a bedform stability diagram.” 2010. Masters Thesis, Universiteit Utrecht. Accessed January 21, 2021.
http://dspace.library.uu.nl:8080/handle/1874/40967.
MLA Handbook (7th Edition):
Mulder, Joost. “Upper flow regime bedform stability - Cyclic steps, their geometry and position in a bedform stability diagram.” 2010. Web. 21 Jan 2021.
Vancouver:
Mulder J. Upper flow regime bedform stability - Cyclic steps, their geometry and position in a bedform stability diagram. [Internet] [Masters thesis]. Universiteit Utrecht; 2010. [cited 2021 Jan 21].
Available from: http://dspace.library.uu.nl:8080/handle/1874/40967.
Council of Science Editors:
Mulder J. Upper flow regime bedform stability - Cyclic steps, their geometry and position in a bedform stability diagram. [Masters Thesis]. Universiteit Utrecht; 2010. Available from: http://dspace.library.uu.nl:8080/handle/1874/40967
Delft University of Technology
4.
Termes, A.P.P. (author).
Watermovement over a horizontal bed and solitary sanddune.
Degree: 1984, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:4952bdb8-ad0b-46c7-bdeb-9d3a9f132510
► In order to predict waterlevel changes in rivers due to floodwaves and local bedshapes for navigation, the local behaviour of the riverbed should be known.…
(more)
▼ In order to predict waterlevel changes in rivers due to floodwaves and local bedshapes for navigation, the local behaviour of the riverbed should be known. In many cases the bed of a river ~onsists of dunes, which propagate downstraam due to the sediment transport along the dunes. In this report mainly the watermovement but also the sediment transport along a dune is studied. The investigation consists of a theoretica! and an experimental part. In the theoretica! part a calculation of the flowfield above a dune is carried out using a computer model for the watermovement (ODYSSEE computer program of the Delft Hydraulica Laboratory, DHL). In the experimental part the mechanism of the local sediment transport along the dune is studied. The experimental set up consists of a solitary sanddune on a conveyor belt in a flume. The position of the dune is constant due to: conveyor belt velocity = - propagationvelocity of the dune. In this situation the flowfield above the duneis measured using a Laser Doppier Anemometer (LDA), which is tested first in a uniform flow situation. The local sediment transport, which is known along the steady dune, is related to the local bedshearstress.
Hydraulic Engineering
Civil Engineering and Geosciences
Advisors/Committee Members: De Vries, M. (mentor), Vreugdenhil, C.B. (mentor), Ribberink, J.S. (mentor), Ooms, G. (mentor).
Subjects/Keywords: river dune; bedform; river morphology
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Termes, A. P. P. (. (1984). Watermovement over a horizontal bed and solitary sanddune. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:4952bdb8-ad0b-46c7-bdeb-9d3a9f132510
Chicago Manual of Style (16th Edition):
Termes, A P P (author). “Watermovement over a horizontal bed and solitary sanddune.” 1984. Masters Thesis, Delft University of Technology. Accessed January 21, 2021.
http://resolver.tudelft.nl/uuid:4952bdb8-ad0b-46c7-bdeb-9d3a9f132510.
MLA Handbook (7th Edition):
Termes, A P P (author). “Watermovement over a horizontal bed and solitary sanddune.” 1984. Web. 21 Jan 2021.
Vancouver:
Termes APP(. Watermovement over a horizontal bed and solitary sanddune. [Internet] [Masters thesis]. Delft University of Technology; 1984. [cited 2021 Jan 21].
Available from: http://resolver.tudelft.nl/uuid:4952bdb8-ad0b-46c7-bdeb-9d3a9f132510.
Council of Science Editors:
Termes APP(. Watermovement over a horizontal bed and solitary sanddune. [Masters Thesis]. Delft University of Technology; 1984. Available from: http://resolver.tudelft.nl/uuid:4952bdb8-ad0b-46c7-bdeb-9d3a9f132510
University of Montana
5.
Colaiacomo, Erika J.
Downstream spatial and temporal response to dam removal, White Salmon River, WA.
Degree: MS, 2014, University of Montana
URL: https://scholarworks.umt.edu/etd/4353
► The Condit Dam breach on the White Salmon River (WSR) in Washington provided a unique opportunity to study how a bedrock-confined, gravel-bed river responds to…
(more)
▼ The Condit Dam breach on the White Salmon River (WSR) in Washington provided a unique opportunity to study how a bedrock-confined, gravel-bed river responds to a large influx of fine reservoir sediment. On October 26, 2011, a dynamite explosion breached a hole in the base of the 38 m tall dam, causing rapid reservoir erosion and downstream transport of fine sediment through the 5,300 m of channel separating the reservoir from the mouth of the WSR, where it flows into the Columbia River. In my research, I combined field data, aerial photographs, and LiDAR surveys to measure pre-breach and post-breach geomorphic conditions, up to 9 months after the breach, to assess downstream geomorphic response through a confined reach (reach 1) with forced pool-riffle morphology and a less-confined reach (reach 2) near the river’s mouth. I found that the magnitude and duration of geomorphic adjustment was smaller over riffles than pools and over reach 1 than reach 2. By 3 weeks after the dam breach, pools stored about twice as much of the reservoir-derived sediment (~95,000 cubic m) as riffles (~50,000 cubic m). By 9 months post-breach, nearly all (90%) of the sediment had been evacuated from riffles (~5,000 cubic m remained), whereas about half of the sediment initially stored in pools had been evacuated (~50,000 cubic m remained). Reach 1 stored ~145,000 cubic m within the 3 weeks after the dam breach compared to the 650,000 cubic m stored in reach 2. By 9 months post-breach, the volume of sediment stored in reach 1 (~40,000 cubic m) decreased by 72% and the volume in reach 2 (~490,000 cubic m) decreased by only 25%. I also found significant storage behind large wood deposits and throughout the transition between reach 1 and reach 2. My findings suggest a conceptual model by which reductions in grain and bedform roughness caused by initial sediment deposition in reach 1 contribute to sediment transport and deposition in reach 2. Findings from the WSR can help inform recovery from other sediment disturbances and dam removals.
Subjects/Keywords: disturbance; transport capacity; sediment pulse; grain and bedform roughness
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Colaiacomo, E. J. (2014). Downstream spatial and temporal response to dam removal, White Salmon River, WA. (Masters Thesis). University of Montana. Retrieved from https://scholarworks.umt.edu/etd/4353
Chicago Manual of Style (16th Edition):
Colaiacomo, Erika J. “Downstream spatial and temporal response to dam removal, White Salmon River, WA.” 2014. Masters Thesis, University of Montana. Accessed January 21, 2021.
https://scholarworks.umt.edu/etd/4353.
MLA Handbook (7th Edition):
Colaiacomo, Erika J. “Downstream spatial and temporal response to dam removal, White Salmon River, WA.” 2014. Web. 21 Jan 2021.
Vancouver:
Colaiacomo EJ. Downstream spatial and temporal response to dam removal, White Salmon River, WA. [Internet] [Masters thesis]. University of Montana; 2014. [cited 2021 Jan 21].
Available from: https://scholarworks.umt.edu/etd/4353.
Council of Science Editors:
Colaiacomo EJ. Downstream spatial and temporal response to dam removal, White Salmon River, WA. [Masters Thesis]. University of Montana; 2014. Available from: https://scholarworks.umt.edu/etd/4353
Universiteit Utrecht
6.
Vellinga, A.J.
Morphodynamics of bedforms in a supercritical-flow regime: a depth-resolved numerical modelling approach.
Degree: 2014, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/301315
► Both open-channel flows and density currents are able to create supercritical-flow bedforms. The morphodynamics of these supercritical-flow bedforms are, however, still poorly understood. This is…
(more)
▼ Both open-channel flows and density currents are able to create supercritical-flow bedforms. The
morphodynamics of these supercritical-flow bedforms are, however, still poorly understood. This is
mainly due to a lack of measurements of flow processes occurring within these types of flows. Cyclic
steps have successfully been simulated in open-channel flow using a depth-resolved numerical
model. The equilibrium conditions at which certain supercritical-flow bedforms are stable are
investigated. The temporal variation in Froude number is indicative of at which conditions cyclic
steps are in a macroscopic equilibrium at a variability of grain sizes, discharges and sediment
concentrations. The depth-resolved model provides insight into the dynamic interaction between
velocity structure, shear stresses, and sediment concentrations within the flows and resulting erosion
and deposition patterns, which, in their turn affect the flow-properties again. The velocity structure
downstream of a hydraulic jump displays highest flow velocities near the bed, whilst lowest or even
negative velocities are located at the top of the flow, causing the flow to remain exerting shear
stresses on the bed even after the hydraulic jump. The sediment concentrations within the flow only
decrease after a 30 second, or half a meter lag, causing most of the deposition to take place at the
last two-thirds of subcritical region of the flow. The resulting depositional pattern consists of
upstream-dipping backset laminations deposited on the stoss-side of the
bedform, cross-cut by the
erosive surface of the lee-side of the cyclic step, this interplay between erosion and deposition also
causes an upstream migration of the cyclic steps.
Advisors/Committee Members: Eggenhuisen, J.T., Cartigny, M.J.B..
Subjects/Keywords: morphodynamic; supercritical; flow; bedform; bedforms; cyclic step; cyclic steps; RANS; depth-resolved; numerical; model
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Vellinga, A. J. (2014). Morphodynamics of bedforms in a supercritical-flow regime: a depth-resolved numerical modelling approach. (Masters Thesis). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/301315
Chicago Manual of Style (16th Edition):
Vellinga, A J. “Morphodynamics of bedforms in a supercritical-flow regime: a depth-resolved numerical modelling approach.” 2014. Masters Thesis, Universiteit Utrecht. Accessed January 21, 2021.
http://dspace.library.uu.nl:8080/handle/1874/301315.
MLA Handbook (7th Edition):
Vellinga, A J. “Morphodynamics of bedforms in a supercritical-flow regime: a depth-resolved numerical modelling approach.” 2014. Web. 21 Jan 2021.
Vancouver:
Vellinga AJ. Morphodynamics of bedforms in a supercritical-flow regime: a depth-resolved numerical modelling approach. [Internet] [Masters thesis]. Universiteit Utrecht; 2014. [cited 2021 Jan 21].
Available from: http://dspace.library.uu.nl:8080/handle/1874/301315.
Council of Science Editors:
Vellinga AJ. Morphodynamics of bedforms in a supercritical-flow regime: a depth-resolved numerical modelling approach. [Masters Thesis]. Universiteit Utrecht; 2014. Available from: http://dspace.library.uu.nl:8080/handle/1874/301315
Delft University of Technology
7.
De Koning, R.J. (author).
Sand wave dynamics: Bedform analysis and dredging strategy design for South Channel, Melbourne, Australia.
Degree: 2017, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:e9abf2e8-5ecb-49f9-a7aa-ca4cd787fde4
► The study into sand wave dynamics in South Channel has commenced after large dune forms were observed in monitoring campaigns following the channel deepening project…
(more)
▼ The study into sand wave dynamics in South Channel has commenced after large dune forms were observed in monitoring campaigns following the channel deepening project of the Port of Melbourne. The project involved deepening of the harbour berths and channels, but more importantly, it involved the deepening of South Channel in Port Phillip Bay. South Channel, the main shipping channel, crosses the bay over a distance of ≈20km. The growth of bedforms at various locations in South Channel now threatens to impede marine traffic. The dimensions and migration rate of the bedforms in the channel are remarkable, especially in the harsh flow conditions in the narrow channel. Therefore, the bedforms in South Channel cannot be given an obvious classification. The first part of this thesis studies the hypothesis that the bedforms in South Channel can be classified as tidal sand waves. Tidal sand waves are large-scale bedforms generated by recirculating flow cells that drive sediment to the top of a crest, and are commonly observed on shallow coastal seas such as the North Sea. The second part of the thesis explores different dredging strategies for tidal sand wave fields and these are assessed for the case of South Channel. The classification analysis follows two different directions. First, the dimensions of sand waves found globally are compared to the dimensions found in South Channel. Secondly, the flow conditions in the channel are compared to the tidal sand wave flow regime as defined in literature. This bedform issue in the channel properly illustrates the necessity of an evaluation of the current, and alternative, channel maintenance strategies. A numerical model in Delft3D software is used to assess the different strategies. Though the results of the model are promising, they cannot be applied straightforwardly to assess the navigability of South Channel for the various strategies. A probabilistic approach is applied to combine the insights from the numerical model and the survey data to produce the probability of breaching the maintained depth for the different strategies.
Civil Engineering and Geosciences
Hydraulic Engineering
Coastal Engineering
Advisors/Committee Members: Aarninkhof, S.G.J. (mentor).
Subjects/Keywords: sandwave; sand wave; south channel; Melbourne; bedform; dredging; prediction; classification; modelling; delft3d
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
De Koning, R. J. (. (2017). Sand wave dynamics: Bedform analysis and dredging strategy design for South Channel, Melbourne, Australia. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:e9abf2e8-5ecb-49f9-a7aa-ca4cd787fde4
Chicago Manual of Style (16th Edition):
De Koning, R J (author). “Sand wave dynamics: Bedform analysis and dredging strategy design for South Channel, Melbourne, Australia.” 2017. Masters Thesis, Delft University of Technology. Accessed January 21, 2021.
http://resolver.tudelft.nl/uuid:e9abf2e8-5ecb-49f9-a7aa-ca4cd787fde4.
MLA Handbook (7th Edition):
De Koning, R J (author). “Sand wave dynamics: Bedform analysis and dredging strategy design for South Channel, Melbourne, Australia.” 2017. Web. 21 Jan 2021.
Vancouver:
De Koning RJ(. Sand wave dynamics: Bedform analysis and dredging strategy design for South Channel, Melbourne, Australia. [Internet] [Masters thesis]. Delft University of Technology; 2017. [cited 2021 Jan 21].
Available from: http://resolver.tudelft.nl/uuid:e9abf2e8-5ecb-49f9-a7aa-ca4cd787fde4.
Council of Science Editors:
De Koning RJ(. Sand wave dynamics: Bedform analysis and dredging strategy design for South Channel, Melbourne, Australia. [Masters Thesis]. Delft University of Technology; 2017. Available from: http://resolver.tudelft.nl/uuid:e9abf2e8-5ecb-49f9-a7aa-ca4cd787fde4
Virginia Tech
8.
Wizevich, Michael Charles.
Sedimentology and Regional Implications of Fluvial Quartzose Sandstones of the Lee Formation, Central Appalachian Basin.
Degree: PhD, Geography, 1991, Virginia Tech
URL: http://hdl.handle.net/10919/38113
► Sedimentological analyses, including detailed facies characterization and lateral profiling, demonstrate deposition in a bedload-dominated fluvial system for the quartzose sandstones of Lee Formation. Internal (architectural)…
(more)
▼ Sedimentological analyses, including detailed facies characterization and lateral profiling, demonstrate deposition in a bedload-dominated fluvial system for the quartzose sandstones of Lee Formation. Internal (architectural) elements of the sandstones consist primarily of uuncated channel-fIll sequences. Individual channel elements, up to 20 meters thick, contain a complex hierarchy of
bedform deposits. The principal internal component of channels were downstream-accreting (mid-channel?) macroforms; channel elements frequently contain deposits of more than one macroform. Reconstruction of the macroforms reveals accretion primarily by superposed bedforms that migrated down a lowangle front. Steeper, giant foresets, transitional along flow with the low-angle facies, indicate that the macroform episodically developed a steep slipface. Uppermost channels within the Rockcastle Member contain macroform elements with components of lateral accretion, interpreted as deposits of alternate bank-attached macroforms. Also recognized within channel-fill deposits are minor-channel, sandy-
bedform, gravity-flow (attributed to bank slumping), and channel-bottom elements. The latter element is contained within a facies sequence that suggests rising- to flood- to waning-stage deposition. In general, deposition was probably during relatively high stage; little evidence of low-stage flow was recognized. Subordinate fme-grained facies are interpreted as levee and overbank deposits.
Strongly unimodal paleocurrents, lack of facies that suggest low-stage reworking and paucity of lateral-accretion features indicate deposition in a single-channel, low-sinuousity, system (i.e., a low braiding index). Fluvial architecture similar to that found in the Lee Formation has been previously explained by deposition in multi-channel, braided-river systems. However, the internal architecture of sandstone members is also consistent with a single-channel origin. Individual channels were temporarily confined, during which time the passage of several macroforms aggraded the channel. Position of the channel in the alluvial plain was largely controlled by avulsion of the river from fully aggraded channel belts to other areas of the plain. Calculations reveal that avulsion of a single-channel system across a wide alluvial plain is a plausible mechanism for building the sheet-like sandstone bodies of the Lee Formation. Spatial arrangement of individual sandstone members of the Lee Formation was probably controlled by tectonic processes. Episodic thrust-loading in the orogenic belt to the east and subsequent flexure of the crust in the foreland basin caused a step-wise progression of the river system towards the west.
Advisors/Committee Members: Eriksson, Kenneth A. (committeechair), Scheckler, Stephen E. (committee member), Read, James Fredrick (committee member), Glover, Lynn III (committee member), Bambach, Richard K. (committee member).
Subjects/Keywords: bedform deposits; LD5655.V856 1991.W594
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wizevich, M. C. (1991). Sedimentology and Regional Implications of Fluvial Quartzose Sandstones of the Lee Formation, Central Appalachian Basin. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/38113
Chicago Manual of Style (16th Edition):
Wizevich, Michael Charles. “Sedimentology and Regional Implications of Fluvial Quartzose Sandstones of the Lee Formation, Central Appalachian Basin.” 1991. Doctoral Dissertation, Virginia Tech. Accessed January 21, 2021.
http://hdl.handle.net/10919/38113.
MLA Handbook (7th Edition):
Wizevich, Michael Charles. “Sedimentology and Regional Implications of Fluvial Quartzose Sandstones of the Lee Formation, Central Appalachian Basin.” 1991. Web. 21 Jan 2021.
Vancouver:
Wizevich MC. Sedimentology and Regional Implications of Fluvial Quartzose Sandstones of the Lee Formation, Central Appalachian Basin. [Internet] [Doctoral dissertation]. Virginia Tech; 1991. [cited 2021 Jan 21].
Available from: http://hdl.handle.net/10919/38113.
Council of Science Editors:
Wizevich MC. Sedimentology and Regional Implications of Fluvial Quartzose Sandstones of the Lee Formation, Central Appalachian Basin. [Doctoral Dissertation]. Virginia Tech; 1991. Available from: http://hdl.handle.net/10919/38113
University of South Carolina
9.
Nelson, Timothy Robert.
A 2-D Time-Dependent Ripple Prediction Model for Wave Dominated Flows.
Degree: MS, Earth and Ocean Sciences, 2011, University of South Carolina
URL: https://scholarcommons.sc.edu/etd/1337
► The development of a new 2-D, time dependent ripple prediction model is presented which allows for the prediction of ripple wavelength, height and orientation.…
(more)
▼ The development of a new 2-D, time dependent ripple prediction model is presented which allows for the prediction of ripple wavelength, height and orientation. The model is an extension to that developed by Traykovski (2007) and uses an equilibrium ripple sub-module that provides the target geometry of the sea bed. Temporal variability of the hydrodynamic conditions causes ripple geometry to lag behind and not always agree with that predicted by existing equilibrium models. The new model has the ability to predict the irregularity of the sea bed, something not achievable with the 1-D model. A comparison of the 2-D and 1-D models is carried out under a variety of synthetic wave forcing conditions and equilibrium ripple models and the predicted ripple characteristics are compared. The results show that for a constant wave direction, both the 1-D and 2-D models are in agreement. However, under changing wave directions, the 2-D model predicts a significant lower ripple height during transition from one ripple state to another. In addition, two new parameters provided by the 2-D model, defined as the normalized wavelength and orientation spectral width provide an indication of the
bedform irregularity.
Advisors/Committee Members: George Voulgaris.
Subjects/Keywords: Earth Sciences; Geology; Physical Sciences and Mathematics; bedform; ripple; ripple geometry; ripple orientation; time dependent ripple model
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Nelson, T. R. (2011). A 2-D Time-Dependent Ripple Prediction Model for Wave Dominated Flows. (Masters Thesis). University of South Carolina. Retrieved from https://scholarcommons.sc.edu/etd/1337
Chicago Manual of Style (16th Edition):
Nelson, Timothy Robert. “A 2-D Time-Dependent Ripple Prediction Model for Wave Dominated Flows.” 2011. Masters Thesis, University of South Carolina. Accessed January 21, 2021.
https://scholarcommons.sc.edu/etd/1337.
MLA Handbook (7th Edition):
Nelson, Timothy Robert. “A 2-D Time-Dependent Ripple Prediction Model for Wave Dominated Flows.” 2011. Web. 21 Jan 2021.
Vancouver:
Nelson TR. A 2-D Time-Dependent Ripple Prediction Model for Wave Dominated Flows. [Internet] [Masters thesis]. University of South Carolina; 2011. [cited 2021 Jan 21].
Available from: https://scholarcommons.sc.edu/etd/1337.
Council of Science Editors:
Nelson TR. A 2-D Time-Dependent Ripple Prediction Model for Wave Dominated Flows. [Masters Thesis]. University of South Carolina; 2011. Available from: https://scholarcommons.sc.edu/etd/1337
10.
-0507-5442.
Nitrate removal efficiency in hyporheic zones : the effect of temperature and bedform dynamics.
Degree: PhD, Geological Sciences, 2017, University of Texas – Austin
URL: http://hdl.handle.net/2152/62599
► Fundamental understanding of bedform-induced hyporheic flow and how it controls the nitrate dynamics in the hyporheic zone (HZ) is critical for environmental and ecological problems,…
(more)
▼ Fundamental understanding of
bedform-induced hyporheic flow and how it controls the nitrate dynamics in the hyporheic zone (HZ) is critical for environmental and ecological problems, such as eutrophication, deterioration of water quality, and loss of biodiversity. The HZ is regarded as a biogeochemical hotspot for removing nitrate from the river system. Although hyporheic flux has been extensively studied in the HZ in the last decade, the cycle of nitrate dynamics in the HZ is still poorly understood. To better characterize and predict nitrate cycling in the HZ, I have investigated the role of HZ in removing nitrate in response to temperature variations and
bedform migration through numerical experiments.
I have designed and generated all
bedform shapes for this dissertation. All numerical experiments followed the same sequential procedures: (1) Solving Reynolds-averaged Navier-Stokes equations to obtain pressure distribution along the sediment-water interface; (2) The
bedform-induced pressure along sediment-water interface drives water entering into and out of HZ by solving the Darcy’s equation; (3) Meanwhile, the transport equations were implemented for solving reactive species and/or temperature distributions, depending on whether temperature was assumed to be spatially heterogeneous or homogeneous. The reactive species were either consumed or produced that was closely related to the reaction chains for the nitrate transformations in the HZ. Here, we only considered aerobic respiration, denitrification, and nitrification for nitrate cycling in the HZ.
My dissertation started with the simplest cases assuming uniform temperature in the HZ. I found that nitrate transformations in the HZ are temperature-dependent since the chemical reaction rates increase with enlarging temperature. The functionality of HZ acting as nitrate source or sink depends strongly on the stream water quality. When the HZ serves as nitrate sink, the nitrate removal efficiency increases with temperature. Moreover, since temperature changes diurnally following a sinusoidal function, a persistent biogeochemical hotspot for removing nitrate is present regardless of the occurrence of dynamic and complex hyporheic temperature patterns. The daily-averaged nitrate removal efficiency with instantaneously changing temperature is fairly identical to the counterpart by using uniform temperature in the HZ. Last but not least, I generated more realistic moving ripple bedforms. The migration rate of ripples causes different hyporheic flux and thus reactive transport processes in the HZ. I found that the nitrate removal efficiency increases asymptotically with Damkohler number, and the immobile ripples overestimate the nitrate removal efficiency compared to that for mobile ripples. All above-mentioned research results can be readily extended for large scales.
Advisors/Committee Members: Cardenas, Meinhard Bayani (advisor), Bennett, Philip C (committee member), Mohrig, David (committee member), Werth, Charles J. (committee member), Moffett, Kevan B. (committee member).
Subjects/Keywords: Nitrate removal; Hyporheic zones; Temperature; Bedform dynamics
…efficiency in bedform-induced hyporheic zones… …87
4.3.1 Choice of representative bedform geometry (ripple)… …105
4.4.4 Impact of bedform celerity on denitrification and nitrification… …125
Appendix A3. Parameters for bedform geometry and results for simulations ........... 128… …127
Table A3.1: Parameters for bedform geometry in our study (50 cases)…
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
-0507-5442. (2017). Nitrate removal efficiency in hyporheic zones : the effect of temperature and bedform dynamics. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/62599
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-0507-5442. “Nitrate removal efficiency in hyporheic zones : the effect of temperature and bedform dynamics.” 2017. Doctoral Dissertation, University of Texas – Austin. Accessed January 21, 2021.
http://hdl.handle.net/2152/62599.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-0507-5442. “Nitrate removal efficiency in hyporheic zones : the effect of temperature and bedform dynamics.” 2017. Web. 21 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-0507-5442. Nitrate removal efficiency in hyporheic zones : the effect of temperature and bedform dynamics. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2017. [cited 2021 Jan 21].
Available from: http://hdl.handle.net/2152/62599.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-0507-5442. Nitrate removal efficiency in hyporheic zones : the effect of temperature and bedform dynamics. [Doctoral Dissertation]. University of Texas – Austin; 2017. Available from: http://hdl.handle.net/2152/62599
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
11.
LIM KIAN YEW.
AN EXPERIMENTAL STUDY ON MEAN FLOW CHARACTERISTICS FOR NEAR-ORTHOGONAL COMBINED WAVES AND CURRENTS.
Degree: 2013, National University of Singapore
URL: http://scholarbank.nus.edu.sg/handle/10635/48283
Subjects/Keywords: wave-current; boundary layer; bottom roughness; Grant-Madsen model; mass transport flow; bedform
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
YEW, L. K. (2013). AN EXPERIMENTAL STUDY ON MEAN FLOW CHARACTERISTICS FOR NEAR-ORTHOGONAL COMBINED WAVES AND CURRENTS. (Thesis). National University of Singapore. Retrieved from http://scholarbank.nus.edu.sg/handle/10635/48283
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
YEW, LIM KIAN. “AN EXPERIMENTAL STUDY ON MEAN FLOW CHARACTERISTICS FOR NEAR-ORTHOGONAL COMBINED WAVES AND CURRENTS.” 2013. Thesis, National University of Singapore. Accessed January 21, 2021.
http://scholarbank.nus.edu.sg/handle/10635/48283.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
YEW, LIM KIAN. “AN EXPERIMENTAL STUDY ON MEAN FLOW CHARACTERISTICS FOR NEAR-ORTHOGONAL COMBINED WAVES AND CURRENTS.” 2013. Web. 21 Jan 2021.
Vancouver:
YEW LK. AN EXPERIMENTAL STUDY ON MEAN FLOW CHARACTERISTICS FOR NEAR-ORTHOGONAL COMBINED WAVES AND CURRENTS. [Internet] [Thesis]. National University of Singapore; 2013. [cited 2021 Jan 21].
Available from: http://scholarbank.nus.edu.sg/handle/10635/48283.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
YEW LK. AN EXPERIMENTAL STUDY ON MEAN FLOW CHARACTERISTICS FOR NEAR-ORTHOGONAL COMBINED WAVES AND CURRENTS. [Thesis]. National University of Singapore; 2013. Available from: http://scholarbank.nus.edu.sg/handle/10635/48283
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
12.
Knox, Richard Leo.
Changes in recent effective discharge and geomorphology near the Old River Control on the lower Mississippi River.
Degree: MA, Geography, 2013, University of Texas – Austin
URL: http://hdl.handle.net/2152/21806
► The Mississippi River is considered the ultimate single channel meandering river. Five hundred km upstream from its mouth, about 25% of the river’s discharge is…
(more)
▼ The Mississippi River is considered the ultimate single channel meandering river. Five hundred km upstream from its mouth, about 25% of the river’s discharge is diverted into the Atchafalaya River. This diversion is controlled by the Old River Control structure, built by the US Army Corps of Engineers in stages since 1963, to stop the avulsion of the Mississippi River into the Atchafalaya. The study area is a 119 km sandy bedded reach near Old River Control that is highly impacted by engineering measures. Channel dimensions average 1,000 m wide with average thalweg depths of 23 m. The mean annual discharge is 15,000 m3s-1 with a water surface slope of 0.06 m per river mile.
In a sandy bedded river, the effective discharge is the discharge which cumulatively transports the most sand. This study evaluates how the Old River Control structure has influenced an adjusting effective discharge between 1978 and 2011. The bed load component of sand transport is included by employing a novel, automated, cross-correlation technique. It was found that the upper limit for discharges that cumulatively transport 85% of the total sand load has decreased from 34,000 m3s-1 to 28,000 m3s-1 between 1978 and 2011. Sand transport from 1982 to 2011 occurred during progressively greater ratios of water discharge to the Atchafalaya River and corresponded to an aggradational trend in the nearby Mississippi River at Red River Landing stream gage. The combination of this sand transport trend and nearby channel aggradation is some indication that the diversion may not be stable and that the avulsion of the lower Mississippi River is ongoing. However, sand was transported at similar discharge ratios in the 1978 to 1982 and 2002 to 2011 periods. Future trends will reveal definitively if these findings indicate that the lower Mississippi River avulsion is continuing.
Two aims are pursued by placing the effective discharge approach into the geomorphologic context of the study area. Ten zones are categorized by four distinct geomorphologic classes: meander, no islands; meander, geologic control; meander, islands and divided flow; and straight zones. One, these classes have merit for future research and are shown to be geomorphologically distinct in several ways: natural levee height and channel planform adjustment relationships, sinuosity and width to depth ratios, and
bedform depth to height scaling. Two, this approach allows the comparison of the effective discharge to the study area’s geomorphology. Process-form linkages can be made between sediment transporting events and the three levels in a fluvial hierarchy: fluvial bedforms and channels, bars, and levees. Median grain size and channel position of sediment samples from these three levels were plotted on combined LiDAR and bathymetric derived cross- sections from specific geomorphologic zones. This analysis indicates that the fluvial hierarchy coincides with the stages of effective discharge but seems to scale to the elevation of natural levees.
This study interjects…
Advisors/Committee Members: Latrubesse, Edgardo (advisor).
Subjects/Keywords: Lower Mississippi River; Old River Control; Effective discharge; Bedform morphology
…82
Table 4.3. Bedform classification scheme consists of a letter for bedform height and
a 2… …or 3 for bedform dimensionality.. ...............................................86
Table… …4.4. Correlation of bedform height and length to depth by linear regression for
each type of… …direction of
bedform movement… …79
Figure 4.7. Two profiles with bedform height (N) and bedform translation (…
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Knox, R. L. (2013). Changes in recent effective discharge and geomorphology near the Old River Control on the lower Mississippi River. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/21806
Chicago Manual of Style (16th Edition):
Knox, Richard Leo. “Changes in recent effective discharge and geomorphology near the Old River Control on the lower Mississippi River.” 2013. Masters Thesis, University of Texas – Austin. Accessed January 21, 2021.
http://hdl.handle.net/2152/21806.
MLA Handbook (7th Edition):
Knox, Richard Leo. “Changes in recent effective discharge and geomorphology near the Old River Control on the lower Mississippi River.” 2013. Web. 21 Jan 2021.
Vancouver:
Knox RL. Changes in recent effective discharge and geomorphology near the Old River Control on the lower Mississippi River. [Internet] [Masters thesis]. University of Texas – Austin; 2013. [cited 2021 Jan 21].
Available from: http://hdl.handle.net/2152/21806.
Council of Science Editors:
Knox RL. Changes in recent effective discharge and geomorphology near the Old River Control on the lower Mississippi River. [Masters Thesis]. University of Texas – Austin; 2013. Available from: http://hdl.handle.net/2152/21806
The Ohio State University
13.
Nichols, Claire Suzanne.
Observations of vertical structures and bedform evolution
with field-scale oscillatory hydrodynamic forcing.
Degree: MS, Civil Engineering, 2008, The Ohio State University
URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1203360725
► Observations of the two-dimensional, time-varying velocity field were obtained with a submersible Particle Image Velocimetry (PIV) system in a field-scale, experimental environment at the O.…
(more)
▼ Observations of the two-dimensional, time-varying
velocity field were obtained with a submersible Particle Image
Velocimetry (PIV) system in a field-scale, experimental environment
at the O. H. Hinsdale Wave Research Laboratory. The observations
were obtained over an irregularly rippled bed with ripple heights
and wavelengths of roughly 1 cm and 10 cm, respectively. These
observations provide the means for new insight on the interaction
between fluid flow and
bedform geometry near and within the wave
bottom boundary layer. First, vortical structures are identified
with a measure of the flow field that estimates the time for a
complete revolution of a vortex, called swirling strength, allowing
for the examination of the generation and ejection of individual
vortical structures. An analysis of these structures reveals that
the swirling strength non-dimensionalized by the wave period is
correlated to the Keulegan-Carpenter number. Second,
bedform
evolution regimes are identified using measures of the
non-dimensional bed stress (the grain roughness Shields parameter),
the non-dimensional pressure gradient (the Sleath parameter), and
the ripple amplitude (the ripple radius of curvature). Bedforms
were found to respond to individual waves by modulating in ripple
amplitude as wave groups passed, even when the Shields parameter
exceeded the critical value for sheet flow. However, when the
Sleath parameter exceeded the critical value for plug flow, the
bedform profile flattened requiring time after the wave group
passed to rebuild the ripples.
Advisors/Committee Members: Foster, Diane (Advisor).
Subjects/Keywords: Civil Engineering; Engineering; vortex strucures; bedform evolution, field scale, oscillatory
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Nichols, C. S. (2008). Observations of vertical structures and bedform evolution
with field-scale oscillatory hydrodynamic forcing. (Masters Thesis). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1203360725
Chicago Manual of Style (16th Edition):
Nichols, Claire Suzanne. “Observations of vertical structures and bedform evolution
with field-scale oscillatory hydrodynamic forcing.” 2008. Masters Thesis, The Ohio State University. Accessed January 21, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1203360725.
MLA Handbook (7th Edition):
Nichols, Claire Suzanne. “Observations of vertical structures and bedform evolution
with field-scale oscillatory hydrodynamic forcing.” 2008. Web. 21 Jan 2021.
Vancouver:
Nichols CS. Observations of vertical structures and bedform evolution
with field-scale oscillatory hydrodynamic forcing. [Internet] [Masters thesis]. The Ohio State University; 2008. [cited 2021 Jan 21].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1203360725.
Council of Science Editors:
Nichols CS. Observations of vertical structures and bedform evolution
with field-scale oscillatory hydrodynamic forcing. [Masters Thesis]. The Ohio State University; 2008. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1203360725
14.
Wolfert, Hendrik Pieter.
Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands.
Degree: 2001, University Utrecht
URL: https://dspace.library.uu.nl/handle/1874/540
;
URN:NBN:NL:UI:10-1874-540
;
1874/540
;
URN:NBN:NL:UI:10-1874-540
;
https://dspace.library.uu.nl/handle/1874/540
► Integrated spatial planning for river rehabilitation requires insight in the geomorphology of river systems. Procedures are elaborated to implement a functional-geographical approach in geomorphology, in…
(more)
▼ Integrated spatial planning for river rehabilitation requires insight in the geomorphology of river systems. Procedures are elaborated to implement a functional-geographical approach in geomorphology, in which a view of rivers as four-dimensional systems and the use of a process-based hierarchy of spatio-temporal domains is coupled to methods of land evaluation. Geomorphological mapping and map interpretation are important research techniques. Application is exemplified in case studies on lowland streams and rivers in the Netherlands, in which reference situations, process conditions to be fulfilled, suitability of areas and layout of measures are addressed. The natural developments of bedforms in the meandering sand-bed Keersop stream are strongly influenced by seasonal variations in discharge and aquatic macrophyte cover. Differences in the short-term recovery of the Tongelreep, Keersop and Aa streams to meander rehabilitation are caused by differences in bank material composition, but were also influenced through the design of cross-sectional dimensions and bend curvature. Riverine pastures along the small meandering River Dinkel depend on natural levee overbank deposition and in the long term on meander cutoffs, implicating conservation strategies must be based on geomorphological disturbance processes. Analysis of historical migration rates allowed areas suitable for re-meandering along the small River Vecht to be indicated, on the basis of the spatial variability of bank material resistance to erosion. In the embanked River Rhine depositional zone, four types of fluvial styles occurred before channelisation; landform development was related to the channel widthdepht ratio values and the flow velocity over the floodplain. Insights in the Rhine river reach continuum could be incorporated in a cyclical planning procedure, characterised by phases of plan design and plan evaluation, at two different scale levels. Finally, similarities and differences between these case studies are set in a wider perspective and recommendations for river rehabilitation are discussed.
Subjects/Keywords: bedform configuration; channel migration; fluvial sediments; historical maps; meandering; river ecology; spatial planning
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wolfert, H. P. (2001). Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands. (Doctoral Dissertation). University Utrecht. Retrieved from https://dspace.library.uu.nl/handle/1874/540 ; URN:NBN:NL:UI:10-1874-540 ; 1874/540 ; URN:NBN:NL:UI:10-1874-540 ; https://dspace.library.uu.nl/handle/1874/540
Chicago Manual of Style (16th Edition):
Wolfert, Hendrik Pieter. “Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands.” 2001. Doctoral Dissertation, University Utrecht. Accessed January 21, 2021.
https://dspace.library.uu.nl/handle/1874/540 ; URN:NBN:NL:UI:10-1874-540 ; 1874/540 ; URN:NBN:NL:UI:10-1874-540 ; https://dspace.library.uu.nl/handle/1874/540.
MLA Handbook (7th Edition):
Wolfert, Hendrik Pieter. “Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands.” 2001. Web. 21 Jan 2021.
Vancouver:
Wolfert HP. Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands. [Internet] [Doctoral dissertation]. University Utrecht; 2001. [cited 2021 Jan 21].
Available from: https://dspace.library.uu.nl/handle/1874/540 ; URN:NBN:NL:UI:10-1874-540 ; 1874/540 ; URN:NBN:NL:UI:10-1874-540 ; https://dspace.library.uu.nl/handle/1874/540.
Council of Science Editors:
Wolfert HP. Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands. [Doctoral Dissertation]. University Utrecht; 2001. Available from: https://dspace.library.uu.nl/handle/1874/540 ; URN:NBN:NL:UI:10-1874-540 ; 1874/540 ; URN:NBN:NL:UI:10-1874-540 ; https://dspace.library.uu.nl/handle/1874/540
15.
Kleinhans, M.G.
Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers.
Degree: 2002, University Utrecht
URL: https://dspace.library.uu.nl/handle/1874/545
;
URN:NBN:NL:UI:10-1874-545
;
1874/545
;
URN:NBN:NL:UI:10-1874-545
;
https://dspace.library.uu.nl/handle/1874/545
► The general aim of this PhD-project was to gain better understanding of the sediment transport and depositional processes of sand-gravel mixtures in rivers with subaqueous…
(more)
▼ The general aim of this PhD-project was to gain better understanding of
the sediment transport and depositional processes of sand-gravel
mixtures in rivers with subaqueous dunes. The understanding of the
fundamental processes of sediment transport and deposition in channel
beds is crucial for morphological models. Sand-gravel bed rivers have a
mixture of sand and gravel in their beds, and have dunes while the
coarsest sediment is near incipient motion. In this thesis, the sediment
transport, sorting and deposition processes are studied with field
measurements and laboratory experiments.
Existing bedform stability diagrams were shown to be valid for bedforms
observed in sand- gravel bed rivers and experiments, but new bedform
types were identified as well: sand ribbons, barchans and bedload
sheets. When the bed surface is armoured, barchans and sand ribbons are
dependend on the sediment supply from upstream. This supply is often not
predictable from the local hydraulics and sediment characteristics.
A predictor for bedload transport of sediment mixtures was developed by
extending existing deterministic bedload transport predictors to
non-uniform sediment, based on flume experiments reported herein. The
near-bed turbulence is modelled stochastically to obtain realistic
bedload transport rates at incipient motion. The difference in mobility
of small and large grains is represented by hiding-exposure functions.
The transport predictor was tested on data from the river Rhine, the
Netherlands during a discharge wave in 1998. For the measurements, a new
measurement strategy was developed during a discharge wave in 1997,
leading to an uncertainty in transport rates of less than 20%. Strong
time-lag effects were observed in the field that could not be hindcast
by the predictor. Part of the observed hysteresis can be explained by
vertical sorting of bedload sediment by the dunes, combined with the
time lag between dune height development and the changing flow. A record
of vertically sorted sediment is left in the channel bed after a
discharge wave, which is the antecedent sorting for the next discharge
wave, often called history effect'. The entrainment and deposition
depth of the sediment depends on the dune trough level below the average
bed level and therefore on the dune height.
The vertical sorting is in general fining upward by two processes: by
grain flows at the lee side of the dunes, and by grain size-selective
entrainment and deposition in the dune troughs (gravel lag deposit).
Both processes are studied in detail in additional experiments in both
equilibrium and non-equilibrium conditions (discharge events). The
implications of these results for modelling are discussed.
Subjects/Keywords: river; sand; gravel; bedform; sediment transport; sedimentology; sediment sorting; grain flow; flood; bifurcation
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kleinhans, M. G. (2002). Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers. (Doctoral Dissertation). University Utrecht. Retrieved from https://dspace.library.uu.nl/handle/1874/545 ; URN:NBN:NL:UI:10-1874-545 ; 1874/545 ; URN:NBN:NL:UI:10-1874-545 ; https://dspace.library.uu.nl/handle/1874/545
Chicago Manual of Style (16th Edition):
Kleinhans, M G. “Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers.” 2002. Doctoral Dissertation, University Utrecht. Accessed January 21, 2021.
https://dspace.library.uu.nl/handle/1874/545 ; URN:NBN:NL:UI:10-1874-545 ; 1874/545 ; URN:NBN:NL:UI:10-1874-545 ; https://dspace.library.uu.nl/handle/1874/545.
MLA Handbook (7th Edition):
Kleinhans, M G. “Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers.” 2002. Web. 21 Jan 2021.
Vancouver:
Kleinhans MG. Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers. [Internet] [Doctoral dissertation]. University Utrecht; 2002. [cited 2021 Jan 21].
Available from: https://dspace.library.uu.nl/handle/1874/545 ; URN:NBN:NL:UI:10-1874-545 ; 1874/545 ; URN:NBN:NL:UI:10-1874-545 ; https://dspace.library.uu.nl/handle/1874/545.
Council of Science Editors:
Kleinhans MG. Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers. [Doctoral Dissertation]. University Utrecht; 2002. Available from: https://dspace.library.uu.nl/handle/1874/545 ; URN:NBN:NL:UI:10-1874-545 ; 1874/545 ; URN:NBN:NL:UI:10-1874-545 ; https://dspace.library.uu.nl/handle/1874/545
Universiteit Utrecht
16.
Wolfert, Hendrik Pieter.
Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands.
Degree: 2001, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/540
► Integrated spatial planning for river rehabilitation requires insight in the geomorphology of river systems. Procedures are elaborated to implement a functional-geographical approach in geomorphology, in…
(more)
▼ Integrated spatial planning for river rehabilitation requires insight in the geomorphology of river systems. Procedures are elaborated to implement a functional-geographical approach in geomorphology, in which a view of rivers as four-dimensional systems and the use of a process-based hierarchy of spatio-temporal domains is coupled to methods of land evaluation. Geomorphological mapping and map interpretation are important research techniques. Application is exemplified in case studies on lowland streams and rivers in the Netherlands, in which reference situations, process conditions to be fulfilled, suitability of areas and layout of measures are addressed. The natural developments of bedforms in the meandering sand-bed Keersop stream are strongly influenced by seasonal variations in discharge and aquatic macrophyte cover. Differences in the short-term recovery of the Tongelreep, Keersop and Aa streams to meander rehabilitation are caused by differences in bank material composition, but were also influenced through the design of cross-sectional dimensions and bend curvature. Riverine pastures along the small meandering River Dinkel depend on natural levee overbank deposition and in the long term on meander cutoffs, implicating conservation strategies must be based on geomorphological disturbance processes. Analysis of historical migration rates allowed areas suitable for re-meandering along the small River Vecht to be indicated, on the basis of the spatial variability of bank material resistance to erosion. In the embanked River Rhine depositional zone, four types of fluvial styles occurred before channelisation; landform development was related to the channel widthdepht ratio values and the flow velocity over the floodplain. Insights in the Rhine river reach continuum could be incorporated in a cyclical planning procedure, characterised by phases of plan design and plan evaluation, at two different scale levels. Finally, similarities and differences between these case studies are set in a wider perspective and recommendations for river rehabilitation are discussed.
Subjects/Keywords: Aardwetenschappen; bedform configuration; channel migration; fluvial sediments; historical maps; meandering; river ecology; spatial planning
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wolfert, H. P. (2001). Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands. (Doctoral Dissertation). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/540
Chicago Manual of Style (16th Edition):
Wolfert, Hendrik Pieter. “Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands.” 2001. Doctoral Dissertation, Universiteit Utrecht. Accessed January 21, 2021.
http://dspace.library.uu.nl:8080/handle/1874/540.
MLA Handbook (7th Edition):
Wolfert, Hendrik Pieter. “Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands.” 2001. Web. 21 Jan 2021.
Vancouver:
Wolfert HP. Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands. [Internet] [Doctoral dissertation]. Universiteit Utrecht; 2001. [cited 2021 Jan 21].
Available from: http://dspace.library.uu.nl:8080/handle/1874/540.
Council of Science Editors:
Wolfert HP. Geomorphological change and river rehabilitation : case studies on lowland fluvial ystems in the Netherlands. [Doctoral Dissertation]. Universiteit Utrecht; 2001. Available from: http://dspace.library.uu.nl:8080/handle/1874/540
Universiteit Utrecht
17.
Kleinhans, M.G.
Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers.
Degree: 2002, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/545
► The general aim of this PhD-project was to gain better understanding of the sediment transport and depositional processes of sand-gravel mixtures in rivers with subaqueous…
(more)
▼ The general aim of this PhD-project was to gain better understanding of
the sediment transport and depositional processes of sand-gravel
mixtures in rivers with subaqueous dunes. The understanding of the
fundamental processes of sediment transport and deposition in channel
beds is crucial for morphological models. Sand-gravel bed rivers have a
mixture of sand and gravel in their beds, and have dunes while the
coarsest sediment is near incipient motion. In this thesis, the sediment
transport, sorting and deposition processes are studied with field
measurements and laboratory experiments.
Existing bedform stability diagrams were shown to be valid for bedforms
observed in sand- gravel bed rivers and experiments, but new bedform
types were identified as well: sand ribbons, barchans and bedload
sheets. When the bed surface is armoured, barchans and sand ribbons are
dependend on the sediment supply from upstream. This supply is often not
predictable from the local hydraulics and sediment characteristics.
A predictor for bedload transport of sediment mixtures was developed by
extending existing deterministic bedload transport predictors to
non-uniform sediment, based on flume experiments reported herein. The
near-bed turbulence is modelled stochastically to obtain realistic
bedload transport rates at incipient motion. The difference in mobility
of small and large grains is represented by hiding-exposure functions.
The transport predictor was tested on data from the river Rhine, the
Netherlands during a discharge wave in 1998. For the measurements, a new
measurement strategy was developed during a discharge wave in 1997,
leading to an uncertainty in transport rates of less than 20%. Strong
time-lag effects were observed in the field that could not be hindcast
by the predictor. Part of the observed hysteresis can be explained by
vertical sorting of bedload sediment by the dunes, combined with the
time lag between dune height development and the changing flow. A record
of vertically sorted sediment is left in the channel bed after a
discharge wave, which is the antecedent sorting for the next discharge
wave, often called history effect'. The entrainment and deposition
depth of the sediment depends on the dune trough level below the average
bed level and therefore on the dune height.
The vertical sorting is in general fining upward by two processes: by
grain flows at the lee side of the dunes, and by grain size-selective
entrainment and deposition in the dune troughs (gravel lag deposit).
Both processes are studied in detail in additional experiments in both
equilibrium and non-equilibrium conditions (discharge events). The
implications of these results for modelling are discussed.
Subjects/Keywords: Aardwetenschappen; river; sand; gravel; bedform; sediment transport; sedimentology; sediment sorting; grain flow; flood; bifurcation
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kleinhans, M. G. (2002). Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers. (Doctoral Dissertation). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/545
Chicago Manual of Style (16th Edition):
Kleinhans, M G. “Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers.” 2002. Doctoral Dissertation, Universiteit Utrecht. Accessed January 21, 2021.
http://dspace.library.uu.nl:8080/handle/1874/545.
MLA Handbook (7th Edition):
Kleinhans, M G. “Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers.” 2002. Web. 21 Jan 2021.
Vancouver:
Kleinhans MG. Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers. [Internet] [Doctoral dissertation]. Universiteit Utrecht; 2002. [cited 2021 Jan 21].
Available from: http://dspace.library.uu.nl:8080/handle/1874/545.
Council of Science Editors:
Kleinhans MG. Sorting out sand and gravel : sediment transport and deposition in sand-gravel bed rivers. [Doctoral Dissertation]. Universiteit Utrecht; 2002. Available from: http://dspace.library.uu.nl:8080/handle/1874/545
18.
Chapuis, Margot.
Mobilité des sédiments fluviaux grossiers dans les systèmes fortement anthropisés : éléments pour la gestion de la basse vallée de la Durance : Bed mobility in highly modified fluvial systems : keys to understanding for river management (Durance River, South-Eastern France).
Degree: Docteur es, Géographie, 2012, Aix Marseille Université
URL: http://www.theses.fr/2012AIXM3019
► La Durance est une large rivière méditerranéenne à charge grossière et à lit divagant. Le fonctionnement hydro-sédimentaire de son bassin versant a été profondément modifié…
(more)
▼ La Durance est une large rivière méditerranéenne à charge grossière et à lit divagant. Le fonctionnement hydro-sédimentaire de son bassin versant a été profondément modifié par la mise en place d'aménagements hydro-électriques et par les extractions de graviers, qui ont entraîné une rétraction de sa bande active et une incision marquée de son lit. Ces évolutions morphologiques correspondent à des enjeux majeurs en termes de gestion du territoire en moyenne et basse Durance, du fait de la nécessité du maintien d'une capacité d'écoulement du lit en crue, et de la mobilité latérale du lit, souvent incompatible avec l'occupation de la vallée. Cette thèse, basée sur la collecte de données de terrain, vise à développer un schéma de fonctionnement du transport sédimentaire dans les rivières à charge grossière de grande largeur, en intégrant les différentes échelles spatiales (et donc temporelles). Elle a également pour objectif de donner des clefs de compréhension pour la gestion des flux sédimentaires en Durance. Les mécanismes de la mobilité des particules sédimentaires et des formes fluviales sont étudiés dans une démarche ascendante de reformulation scientifique de questionnements opérationnels.
The Durance River (South-Eastern France) is a large and steep wandering gravel-bed river, deeply impacted by gravel mining and flow diversion in its whole catchment area. The Durance River is characterized by a sediment deficit that led to a reduction of active channel width and river bed degradation. These lateral and vertical dynamics lead to important issues in terms of landscape management, because of (i) maintaining the bed hydraulic capacity to evacuate flood discharges and (ii) planform evolution of the river that conflicts with landscape use. This field-based thesis aims at developing a functioning scheme of bedload transport in large gravel bed rivers at various spatial (and consequently temporal) scales and gives keys to understanding for sediment fluxes management on the Durance River. Particle and bedform mobility mechanisms are studied with a scientific approach closely linked to management issues.
Advisors/Committee Members: Lippmann-Provansal, Mireille (thesis director).
Subjects/Keywords: Géomorphologie fluviale; Transport solide; Durance; Gestion des rivières aménagées; Mobilité des particules grossières; Mobilité des formes fluviales; Flux sédimentaires; Rivière torrentielle méditerranéenne; Fluvial geomorphology; Bedload transport; Durance River; River management; Particle mobility; Bedform mobility; Sediment fluxes; Mediterranean mountain stream
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Chapuis, M. (2012). Mobilité des sédiments fluviaux grossiers dans les systèmes fortement anthropisés : éléments pour la gestion de la basse vallée de la Durance : Bed mobility in highly modified fluvial systems : keys to understanding for river management (Durance River, South-Eastern France). (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2012AIXM3019
Chicago Manual of Style (16th Edition):
Chapuis, Margot. “Mobilité des sédiments fluviaux grossiers dans les systèmes fortement anthropisés : éléments pour la gestion de la basse vallée de la Durance : Bed mobility in highly modified fluvial systems : keys to understanding for river management (Durance River, South-Eastern France).” 2012. Doctoral Dissertation, Aix Marseille Université. Accessed January 21, 2021.
http://www.theses.fr/2012AIXM3019.
MLA Handbook (7th Edition):
Chapuis, Margot. “Mobilité des sédiments fluviaux grossiers dans les systèmes fortement anthropisés : éléments pour la gestion de la basse vallée de la Durance : Bed mobility in highly modified fluvial systems : keys to understanding for river management (Durance River, South-Eastern France).” 2012. Web. 21 Jan 2021.
Vancouver:
Chapuis M. Mobilité des sédiments fluviaux grossiers dans les systèmes fortement anthropisés : éléments pour la gestion de la basse vallée de la Durance : Bed mobility in highly modified fluvial systems : keys to understanding for river management (Durance River, South-Eastern France). [Internet] [Doctoral dissertation]. Aix Marseille Université 2012. [cited 2021 Jan 21].
Available from: http://www.theses.fr/2012AIXM3019.
Council of Science Editors:
Chapuis M. Mobilité des sédiments fluviaux grossiers dans les systèmes fortement anthropisés : éléments pour la gestion de la basse vallée de la Durance : Bed mobility in highly modified fluvial systems : keys to understanding for river management (Durance River, South-Eastern France). [Doctoral Dissertation]. Aix Marseille Université 2012. Available from: http://www.theses.fr/2012AIXM3019
University of Illinois – Urbana-Champaign
19.
Palmer, Jessica A.
The flow structure of interacting barchan dunes.
Degree: MS, 0336, 2010, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/15972
► High-resolution particle-image velocimetry (PIV) experiments have been conducted over a fixed-bed to examine the effects of interacting barchan dunes on the flow structure. The barchan…
(more)
▼ High-resolution particle-image velocimetry (PIV) experiments have been conducted over a fixed-bed to examine the effects of interacting barchan dunes on the flow structure. The barchan dune models were based upon an idealized contour map, the shape and dimensions of which were based upon previous empirical studies of dune morphology. The experimental setup comprised two, co-axially aligned barchan dune models that were spaced at different distances apart. Three volumetric ratios (Vr, upstream barchan dune: downstream barchan dune) of 0.025, 0.056, 0.175, replicated the different behaviors of interacting barchan dunes as observed in the field and laboratory by Endo et al. (2004), and were accompanied by an investigation of identically-sized dunes. Models were placed in an Eiffel-type, open-circuit wind tunnel with a working test-section 6090 mm long by 914 mm wide by 457 mm high and a free-stream turbulence intensity of 0.16%. Flow quantification was achieved using particle imaging velocimetry (PIV) at 0.5Hz. PIV measurements of the mean and turbulent flow field were made in the streamwise–wall-normal plane, along the centerline of the barchans(s), at an average Reynolds number of 59,000.
The presence of an upstream barchan dune of equal volume to the downstream barchan dune (Vr=1) induces a ‘sheltering effect’ on the flow, manifested by a significantly shorter separation bubble and both reduced streamwise velocity and turbulence intensity in the downstream barchan dune leeside, as compared to an isolated barchan. The volumetric ratio associated with the ‘splitting’ behavior (Vr=0.175) of Endo et al. (2004) shows enhanced turbulence production over the downstream barchan dune leeside, that is proposed to be caused by interacting shear layers from the up- and down- stream dunes. The upstream dune also creates a shear layer in its leeside that extends onto the stoss-side of the downstream barchan, and is proposed to be responsible for dune ‘splitting’. For volumetric ratios associated with ‘ejection’ and ‘absorption’ behaviors (Vr=0.056 and 0.025, respectively), the upstream barchan dune does not significantly impact the flow in the leeside of the downstream barchan dune. In these cases, the small coherent turbulent structures generated from the upstream dune lose their coherence before reaching the downstream barchan crest, or may reach the downstream dune shear layer but are too insignificant in intensity and size to interact with the larger flow structures generated in the leeside of downstream barchan dune. The upstream dune leeside for the ‘ejection’ and ‘absorption’ behaviors is characterized by smaller separation zone lengths, and smaller turbulence intensities, than the ‘splitting’ behavior. In this case, it is speculated the potential for downstream erosion is reduced and the downstream barchan maintains its morphology.
Advisors/Committee Members: Best, James L. (advisor).
Subjects/Keywords: Turbulent flow; Barchan dunes; bedform; separation zone; reattachment length; dune interactions; Particle-imaging velocimetry (PIV)
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Palmer, J. A. (2010). The flow structure of interacting barchan dunes. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/15972
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Palmer, Jessica A. “The flow structure of interacting barchan dunes.” 2010. Thesis, University of Illinois – Urbana-Champaign. Accessed January 21, 2021.
http://hdl.handle.net/2142/15972.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Palmer, Jessica A. “The flow structure of interacting barchan dunes.” 2010. Web. 21 Jan 2021.
Vancouver:
Palmer JA. The flow structure of interacting barchan dunes. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2010. [cited 2021 Jan 21].
Available from: http://hdl.handle.net/2142/15972.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Palmer JA. The flow structure of interacting barchan dunes. [Thesis]. University of Illinois – Urbana-Champaign; 2010. Available from: http://hdl.handle.net/2142/15972
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
20.
Parker, John Alexandre.
Outcrop analysis of ooid grainstones in the Permian Grayburg Formation, Shattuck Escarpment, New Mexico.
Degree: MSin Geological Sciences, Geological Sciences, 2013, University of Texas – Austin
URL: http://hdl.handle.net/2152/21901
► Ooid grainstone reservoir architecture remains poorly understood, particularly because of sedimentologic and stratigraphic heterogeneities that are innate to grainstone body development. Understanding of Geospatial relationships…
(more)
▼ Ooid grainstone reservoir architecture remains poorly understood, particularly because of sedimentologic and stratigraphic heterogeneities that are innate to grainstone body development. Understanding of Geospatial relationships and recovery of hydrocarbons from these significant reservoir facies can be improved with access to outcrop analog information from well exposed examples.
Object-based models and other modern subsurface reservoir models are considered superior methods for portraying realistic sediment distributions. These models, however, are highly dependent on input data describing sediment-body geometry for faithful template generation. Such input data are notably rare in carbonate systems. Maps generated from modern depositional patterns give a first approximation of areal distribution, but they are not as useful for understanding final preserved stratigraphic thickness and internal facies, sedimentary structure, and grain-type patterns. For this purpose, studies of exceptional outcrops are required. The 18 km long oblique-dip-oriented wall of the Shattuck Escarpment provides such a unique exposure of Permian-age grainstones.
The Shattuck Escarpment in the Guadalupe Mountains provides an oblique-dip profile that exposes a near-complete middle Permian Grayburg mixed clastic-carbonate shelf succession of three high-frequency sequences which contain 30 high-frequency cycles. Particularly important for this study are the four cycles that display full updip to downdip extents of ooid grainstone tidal bar and tidal delta objects. The data from the Shattuck wall presented in this paper focusses on the transgressive portion of the upper Grayburg, or G12 high-frequency sequence (HFS), located 5 km landward of the time-equivalent shelf margin. This interval is an analog for productive fields along the northwest shelf of the Delaware Basin and on the eastern flank of the Central Basin Platform. The goal of this project is to understand the sedimentology and facies/cycle architectural variability of tidally influenced shelf crest ooid grainstones of the Grayburg Formation. Comparing this outcrop data to modern grainstone deposits allows the reader to understand the small-scale and large-scale sedimentologic and architectural patterns in analogous subsurface ooid grainstone reservoirs.
Spatial analysis of these cycles was carried out using measured sections and GigaPan (high resolution photomosaic) data. Petrophysical (Porosity and Permeability) data was collected from three separate vertical core plug transects approximately 1 km apart with a vertical resolution of 30 cm. Cycle-set-scale grainstone complexes up to 6m thick extend at least 4.25 km along depositional dip and show variations in permeability between 6-400 mD and porosities between 8-20% within the lower portions of the grainstone complex.
Advisors/Committee Members: Kerans, C. (Charles), 1954- (advisor).
Subjects/Keywords: Grayburg Formation; Ooid grainstone; Permian; Shattuck Escarpment; Outcrop; Geospatial; Core plug; Cross-stratified; Bedform
…by the same
bedform.
Grainstone objects in outcrop sometimes exhibit a vertical succession…
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Parker, J. A. (2013). Outcrop analysis of ooid grainstones in the Permian Grayburg Formation, Shattuck Escarpment, New Mexico. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/21901
Chicago Manual of Style (16th Edition):
Parker, John Alexandre. “Outcrop analysis of ooid grainstones in the Permian Grayburg Formation, Shattuck Escarpment, New Mexico.” 2013. Masters Thesis, University of Texas – Austin. Accessed January 21, 2021.
http://hdl.handle.net/2152/21901.
MLA Handbook (7th Edition):
Parker, John Alexandre. “Outcrop analysis of ooid grainstones in the Permian Grayburg Formation, Shattuck Escarpment, New Mexico.” 2013. Web. 21 Jan 2021.
Vancouver:
Parker JA. Outcrop analysis of ooid grainstones in the Permian Grayburg Formation, Shattuck Escarpment, New Mexico. [Internet] [Masters thesis]. University of Texas – Austin; 2013. [cited 2021 Jan 21].
Available from: http://hdl.handle.net/2152/21901.
Council of Science Editors:
Parker JA. Outcrop analysis of ooid grainstones in the Permian Grayburg Formation, Shattuck Escarpment, New Mexico. [Masters Thesis]. University of Texas – Austin; 2013. Available from: http://hdl.handle.net/2152/21901
. 
Open Access Theses and Dissertations
