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You searched for subject:(Demak). Showing records 1 – 3 of 3 total matches.

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Delft University of Technology

1. Borsje, Ruben (author). Wave-Driven Set-Up of Fluid Mud: Demak, Indonesia.

Degree: 2019, Delft University of Technology

Demak is a regency within the province of Central Java, Indonesia, with a mud-mangrove coast bordering the Java Sea. The region is facing a rapid retreat of the coastline, threatening the livelihood of a large part of the population. The main cause of the erosion is the deforestation of the green belt of mangroves. This has disturbed the delicate sediment balance in the area drastically. This MSc thesis was carried out within BioManCO. This is a project of Delft University of Technology and Universitas Diponegoro and aims to develop a bio-morphodynamic model for mangrove-mud coasts. This will eventually be used to identify the conditions under which autonomous reforestation of a sustainable mangrove green belt will take place, restoring the natural coastal protection. Semi-permeable dams are already being implemented to restore the sediment balance in the area. In this approach, however, the existence of a fluid mud layer is neglected. The observation of relatively steep slopes of the interface between mud and water indicates potential mud transport within the mud layer. Such a transport would contribute to the shoreward flux of sediment and thus to the restoration of the coastal profile. If a hybrid dam is implemented, it will block the flow of sediment and might therefore defy its own purpose; attenuating flow and waves in order to capture sediment and restore the eroded coastal profile. The objective of this thesis is to assess wave damping as a driving mechanism for set-up of the fluid mud layer at the coast of Demak and to identify under what conditions such a set-up can exist. Significant attenuation of waves can be achieved by viscous dissipation of wave energy in the mud layer. The set-up of the fluid mud interface is hypothesised to be balancing the wave force resulting from the reduction of wave energy in shoreward direction. To gain insight in the damping of waves and, more generally, in the dynamics of the coastal system of Demak, a field campaign has been carried out. Based on these measurements a SWAN-Mud model has been set up and has been coupled to an idealised model that calculates the equilibrium slope based on modelled wave-damping. The field observations show that the interface level is indeed sloping upwards towards the coast. This slope, however, does not seem to change significantly during the field campaign, indicating that the occurring waves are not able to move the layer. A strong daily variation in wave height and period, dependent on the prevailing wind system, is observed. SWAN-Mud is able to reproduce these measurements convincingly, even with the simple schematisation used in this thesis. The damping of the waves is influenced by the water depth and the wave period, and to a lesser extent by the wave height. It is also strongly dependent on the thickness and viscosity of the mud layer. The use of a fluid mud module to model the dissipation of waves at the coast of Demak is proven to be necessary. The developed conceptual model assumes a balance between the wave force in the mud layer… Advisors/Committee Members: Reniers, Ad (mentor), van Maren, Bas (mentor), Winterwerp, Han (graduation committee), de Schipper, Matthieu (graduation committee), Tas, Silke (graduation committee), Delft University of Technology (degree granting institution).

Subjects/Keywords: fluid mud; Building with Nature; mud coast; erosion; sediment transport; Wave Attenuation; wave damping; radiation stress; fieldwork; SWAN; SWAN-Mud; viscous damping; indonesia; Demak; mud; conceptual model; hybrid dam

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APA (6th Edition):

Borsje, R. (. (2019). Wave-Driven Set-Up of Fluid Mud: Demak, Indonesia. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:d51e770e-37ad-4c02-8cbf-c5abceaccc39

Chicago Manual of Style (16th Edition):

Borsje, Ruben (author). “Wave-Driven Set-Up of Fluid Mud: Demak, Indonesia.” 2019. Masters Thesis, Delft University of Technology. Accessed October 21, 2020. http://resolver.tudelft.nl/uuid:d51e770e-37ad-4c02-8cbf-c5abceaccc39.

MLA Handbook (7th Edition):

Borsje, Ruben (author). “Wave-Driven Set-Up of Fluid Mud: Demak, Indonesia.” 2019. Web. 21 Oct 2020.

Vancouver:

Borsje R(. Wave-Driven Set-Up of Fluid Mud: Demak, Indonesia. [Internet] [Masters thesis]. Delft University of Technology; 2019. [cited 2020 Oct 21]. Available from: http://resolver.tudelft.nl/uuid:d51e770e-37ad-4c02-8cbf-c5abceaccc39.

Council of Science Editors:

Borsje R(. Wave-Driven Set-Up of Fluid Mud: Demak, Indonesia. [Masters Thesis]. Delft University of Technology; 2019. Available from: http://resolver.tudelft.nl/uuid:d51e770e-37ad-4c02-8cbf-c5abceaccc39


Delft University of Technology

2. Haage, Samantha (author). Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission.

Degree: 2018, Delft University of Technology

Due to the removal of mangrove forests, coastal zones can suffer from severe erosion. One of the proposed solutions is the construction of permeable structures. This study aims to optimise the design of permeable (brushwood) structures in order to restore the sediment balance and encourage mangrove re-establishment on tropical mud coasts. Preferably wave transmission should be low in order to create a calmer climate behind the structure. In that way sediment is able to settle down, which could lead to a recovery of the mud profile. It is also preferred that reflection by the structure is low. High reflection rates cause scour holes that lead to instability of the structure. Furthermore, scour holes could hinder future mangrove re-establishment. Aiming to achieve low reflection and transmission rates, the dissipation inside the structure has to be as high as possible. Experiments were conducted in the 40 meter wave flume at the Environmental Fluid Mechanics Laboratory at TU Delft. The permeable structure was schematized as an array of cylinders. With the physical scale model various effects could be tested, including the porosity, structure width, arrangement, orientation, etc. The tests were done for 5 different wave cases, from which the wave energy distribution over reflection, dissipation and transmission was determined. The existing brushwood structures require intensive maintenance. This is partly due to the sinking of the material into the soft mud. Also, the brushwood material washes away often as it is lighter than water and difficult to constrain in vertical direction. An alternative design that requires less maintenance would be preferred. Therefore, it was interesting to see whether a comparable amount of wave dissipation could be achieved by using vertical elements only. One important finding is that in more shallow water regions, vertical and horizontal orientations have similar dissipation rates. In water regions that go more towards deep water, the horizontal structures have higher dissipation rates. This can be explained by the relative importance of the horizontal and vertical velocities due to the wave motion. In deep water vertical velocities are relatively high. As the horizontal elements have more exposure to this component in comparison to the vertical elements, they provide more dissipation. In shallow water the relative importance of the vertical velocities is lower, which explains the similar dissipation rates of the two orientations. The analytical model of Dalrymple (1984) was used to describe the energy dissipation through the structures. Drag coefficients were derived by using the calibration method. For KC<15 the drag coefficients start increasing. This is possibly due to the relative importance of the inertia force. Comparing the drag coefficients to the ones derived from direct force and velocity measurements in previous studies showed relative high values. This could be due to an underestimation of the horizontal velocity due to the wave motion. The velocity that is used is the… Advisors/Committee Members: Gijón Mancheño, Alejandra (mentor), Sirks, Emma (mentor), Uijttewaal, Wim (graduation committee), Kuiper, Coen (graduation committee), Hofland, Bas (graduation committee), Winterwerp, Han (graduation committee), Delft University of Technology (degree granting institution).

Subjects/Keywords: Building with Nature; Brushwood structures; Demak; Indonesia; BioManCo; Mangroves; Wave flume experiments; Permeable Structures; Physical scale model; Wave dissipation; Cylinders; Drag coefficients; Arrays of Cylinders; Wave Energy Balance; Dalrymple

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Haage, S. (. (2018). Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c

Chicago Manual of Style (16th Edition):

Haage, Samantha (author). “Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission.” 2018. Masters Thesis, Delft University of Technology. Accessed October 21, 2020. http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c.

MLA Handbook (7th Edition):

Haage, Samantha (author). “Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission.” 2018. Web. 21 Oct 2020.

Vancouver:

Haage S(. Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission. [Internet] [Masters thesis]. Delft University of Technology; 2018. [cited 2020 Oct 21]. Available from: http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c.

Council of Science Editors:

Haage S(. Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission. [Masters Thesis]. Delft University of Technology; 2018. Available from: http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c


Delft University of Technology

3. Julianus, E.J.B. (author). The development of a fine sediment nourishment strategy for the rehabilitation of an eroding mangrove-mud coast: Case study on the village Bedono in Indonesia.

Degree: 2016, Delft University of Technology

Civil Engineering and Geosciences

Hydraulic Engineering

Advisors/Committee Members: Winterwerp, J.C. (mentor), Stive, M.J.F. (mentor), van Thiel de Vries, J.S.M. (mentor), Van der Goot, F. (mentor), Van der Wegen, M. (mentor).

Subjects/Keywords: Indonesia; Building with Nature; fine sediment; nourishment; rehabilitation; mangroves; Delft3D Flexible Mesh; DELWAQ; Demak

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Julianus, E. J. B. (. (2016). The development of a fine sediment nourishment strategy for the rehabilitation of an eroding mangrove-mud coast: Case study on the village Bedono in Indonesia. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:597562b3-33df-470c-b97a-3116332424f3

Chicago Manual of Style (16th Edition):

Julianus, E J B (author). “The development of a fine sediment nourishment strategy for the rehabilitation of an eroding mangrove-mud coast: Case study on the village Bedono in Indonesia.” 2016. Masters Thesis, Delft University of Technology. Accessed October 21, 2020. http://resolver.tudelft.nl/uuid:597562b3-33df-470c-b97a-3116332424f3.

MLA Handbook (7th Edition):

Julianus, E J B (author). “The development of a fine sediment nourishment strategy for the rehabilitation of an eroding mangrove-mud coast: Case study on the village Bedono in Indonesia.” 2016. Web. 21 Oct 2020.

Vancouver:

Julianus EJB(. The development of a fine sediment nourishment strategy for the rehabilitation of an eroding mangrove-mud coast: Case study on the village Bedono in Indonesia. [Internet] [Masters thesis]. Delft University of Technology; 2016. [cited 2020 Oct 21]. Available from: http://resolver.tudelft.nl/uuid:597562b3-33df-470c-b97a-3116332424f3.

Council of Science Editors:

Julianus EJB(. The development of a fine sediment nourishment strategy for the rehabilitation of an eroding mangrove-mud coast: Case study on the village Bedono in Indonesia. [Masters Thesis]. Delft University of Technology; 2016. Available from: http://resolver.tudelft.nl/uuid:597562b3-33df-470c-b97a-3116332424f3

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