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You searched for subject:(Rayleigh B nard). Showing records 1 – 2 of 2 total matches.

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Virginia Tech

1. Mehrvarzi, Christopher Omid. Active Transport in Chaotic Rayleigh-Be?nard Convection.

Degree: MS, Mechanical Engineering, 2014, Virginia Tech

The transport of a species in complex flow fields is an important phenomenon related to many areas in science and engineering. There has been significant progress theoretically and experimentally in understanding active transport in steady, periodic flows such as a chain of vortices but many open questions remain for transport in complex and chaotic flows. This thesis investigates the active transport in a three-dimensional, time-dependent flow field characterized by a spatiotemporally chaotic state of Rayleigh-Be?nard convection. A nonlinear Fischer-Kolmogorov-Petrovskii-Piskunov reaction is selected to study the transport within these flows. A highly efficient, parallel spectral element approach is employed to solve the Boussinesq and the reaction-advection-diffusion equations in a spatially-extended cylindrical domain with experimentally relevant boundary conditions. The transport is quantified using statistics of spreading and in terms of active transport characteristics like front speed and geometry and are compared with those results for transport in steady flows found in the literature. The results of the simulations indicate an anomalous diffusion process with a power law 2 < ? < 5/2 a result that deviates from other superdiffusive processes in simpler flows, and reveals that the presence of spiral defect chaos induces strongly anomalous transport. Additionally, transport was found to most likely occur in a direction perpendicular to a convection roll in the flow field. The presence of the spiral defect chaos state of the fluid convection is found to enhance the front perimeter by t3/2 and by a perimeter enhancement ratio r(p) = 2.3. Advisors/Committee Members: Paul, Mark R. (committeechair), Tafti, Danesh K. (committee member), Behkam, Bahareh (committee member).

Subjects/Keywords: Transport; Rayleigh-B'{e}nard convection; Spatiotemporal chaos

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

APA (6th Edition):

Mehrvarzi, C. O. (2014). Active Transport in Chaotic Rayleigh-Be?nard Convection. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/51806

Chicago Manual of Style (16th Edition):

Mehrvarzi, Christopher Omid. “Active Transport in Chaotic Rayleigh-Be?nard Convection.” 2014. Masters Thesis, Virginia Tech. Accessed November 13, 2019. http://hdl.handle.net/10919/51806.

MLA Handbook (7th Edition):

Mehrvarzi, Christopher Omid. “Active Transport in Chaotic Rayleigh-Be?nard Convection.” 2014. Web. 13 Nov 2019.

Vancouver:

Mehrvarzi CO. Active Transport in Chaotic Rayleigh-Be?nard Convection. [Internet] [Masters thesis]. Virginia Tech; 2014. [cited 2019 Nov 13]. Available from: http://hdl.handle.net/10919/51806.

Council of Science Editors:

Mehrvarzi CO. Active Transport in Chaotic Rayleigh-Be?nard Convection. [Masters Thesis]. Virginia Tech; 2014. Available from: http://hdl.handle.net/10919/51806

2. Muddu, Radha Malini Gowri. Three Dimensional Simulation of Rayleigh-B?nard Convection for Rapid Microscale Polymerase Chain Reaction.

Degree: 2012, Texas A&M University

Rayleigh-B?nard convection has been extensively studied in literature owing to its ubiquitous nature. However, most of the studies have been confined to geometries where the aspect ratio of the cylinder was less than 1. Here we study the motion of fluid in geometries with aspect ratio greater than 1, with particular application to use of such motion to actuate biochemical reactions, such as the polymerase chain reaction. We show that it is possible to accelerate the rate of reaction by using a geometry that promotes chaotic motion versus a geometry that promotes quasi- periodic motion. We also simulate chemical kinetics using the fluid motion as a starting point and we prove that chaotic motion indeed enhances the rate of the reaction. We also provide qualitative and quantitative measures for chaotic motion in a fluid flow, which helps to distinguish between different types of fluid motion. We highlight the transitions between different types of flow that are possible with Rayleigh-B?nard convection. Finally, we compare our simulations against experimental data obtained from particle image velocimetry, laser induced fluorescence and optical microscopic visualization. Advisors/Committee Members: Hassan, Yassin A. (advisor), Ugaz, Victor M. (advisor), Marlow, William (committee member), Chen, Hamn-Ching (committee member).

Subjects/Keywords: Rayleigh-B?nard convection; polymerase chain reaction

…increase in concentration of dsDNA Ra Rayleigh number Re Reynolds number Rg radius of… …1 Rayleigh-Bénard convection… …101 xi LIST OF FIGURES FIGURE Page 1 Schematic of Rayleigh-Bénard convection in a… …reaction times in the RB-PCR device ................................ 11 9 Spectrum of Rayleigh… …Rayleigh numbers.............................................. 58 Plots of the z velocity… 

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

APA (6th Edition):

Muddu, R. M. G. (2012). Three Dimensional Simulation of Rayleigh-B?nard Convection for Rapid Microscale Polymerase Chain Reaction. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8780

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):

Muddu, Radha Malini Gowri. “Three Dimensional Simulation of Rayleigh-B?nard Convection for Rapid Microscale Polymerase Chain Reaction.” 2012. Thesis, Texas A&M University. Accessed November 13, 2019. http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8780.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Muddu, Radha Malini Gowri. “Three Dimensional Simulation of Rayleigh-B?nard Convection for Rapid Microscale Polymerase Chain Reaction.” 2012. Web. 13 Nov 2019.

Vancouver:

Muddu RMG. Three Dimensional Simulation of Rayleigh-B?nard Convection for Rapid Microscale Polymerase Chain Reaction. [Internet] [Thesis]. Texas A&M University; 2012. [cited 2019 Nov 13]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8780.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Muddu RMG. Three Dimensional Simulation of Rayleigh-B?nard Convection for Rapid Microscale Polymerase Chain Reaction. [Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8780

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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