Current Search: Boundary layer control (x)
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 Title
 Boundary Layer Control on a Circular Cylindrical Body through Oscillating Lorentz Forcing.
 Creator
 Seltzer, Ryan K., Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

Boundary layer control on a circular cylindrical body through oscillating Lorentz forcing is studied by means of numerical simulation of the vorticitystream function formulation of the NavierStokes equations. The model problem considers axisymmetric seawater flow along an infinite cylinder controlled by an idealized radially directed Lorentz force oscillating spatially and temporally. Under optimum forcing parameters, it is shown that sustainable Lorentz induced vortex rings can travel...
Show moreBoundary layer control on a circular cylindrical body through oscillating Lorentz forcing is studied by means of numerical simulation of the vorticitystream function formulation of the NavierStokes equations. The model problem considers axisymmetric seawater flow along an infinite cylinder controlled by an idealized radially directed Lorentz force oscillating spatially and temporally. Under optimum forcing parameters, it is shown that sustainable Lorentz induced vortex rings can travel along the cylinder at a speed equivalent to the phase speed of forcing . Wall stress is shown to locally change sign in the region adjacent to the vortex, considerably decreasing net viscous drag . Adverse flow behaviors are revealed as a result of studying the effects of the Reynolds numbers, strength of the Lorentz force, and phase speed of forcing for boundary layer control. Adverse flow behaviors inc I ude complex vortex configurations found for suboptimal forcing resulting in a considerable increase in wall stress.
Show less  Date Issued
 2007
 PURL
 http://purl.flvc.org/fau/fd/FA00012549
 Subject Headings
 Mathematical physics, Lorentz transformations, Boundary layer control, Fluid dynamics
 Format
 Document (PDF)
 Title
 Tearing of an aligned vortex by a current difference in twolayer quasigeostrophic flow.
 Creator
 Parthasarathy, Balaji., Florida Atlantic University, Marshall, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

A study of twolayer quasigeostrophic vortex flow is performed to determine the effect of a current difference between the layers on a vortex initially extending through both the layers. In particular, the conditions under which the current difference can 'tear' the vortex are examined. In the first set of flows studied, the current difference is generated by a (stronger) third vortex in the upper layer located at a large distance from the (weaker) vortex under study. A set of flows are also...
Show moreA study of twolayer quasigeostrophic vortex flow is performed to determine the effect of a current difference between the layers on a vortex initially extending through both the layers. In particular, the conditions under which the current difference can 'tear' the vortex are examined. In the first set of flows studied, the current difference is generated by a (stronger) third vortex in the upper layer located at a large distance from the (weaker) vortex under study. A set of flows are also considered in which an ambient geostrophic current difference is produced by a nonuniform background potential vorticity field. The results of the study will be useful in determining the conditions under which large geophysical vortex structures, such as cyclones and ocean rings, can extend to large depths even though the mean currents in the ambient flow change significantly along the vortex length.
Show less  Date Issued
 1993
 PURL
 http://purl.flvc.org/fcla/dt/14909
 Subject Headings
 Vortexmotion, Fluid dynamics, Boundary layer control, Flow visualization
 Format
 Document (PDF)
 Title
 Wind effect on supertall buildings using computational fluid dynamics and structural dynamics.
 Creator
 Assaad, Bilal, Arockiasamy, Madasamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
 Abstract/Description

Supertall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 710 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of...
Show moreSupertall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 710 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of Computational Fluid Dynamics has created an additional layer of analysis and loading prediction alternative to conventional methods. The present document uses turbulence modeling and numerical algorithms by means of Reynoldsaveraged NavierStokes and Large Eddy Simulation equations applied to a square prismatic prototype structure in which its dynamic properties have also been investigated. With proper modeling of the atmospheric boundary layer flow, these numerical techniques reveal important aerodynamic properties and enhance flow visualization to structural engineers in a virtual environment.
Show less  Date Issued
 2015
 PURL
 http://purl.flvc.org/fau/fd/FA00004343, http://purl.flvc.org/fau/fd/FA00004343
 Subject Headings
 Boundary layer control, Buildings  Aerodynamics, Computational fluid dynamics, Structural dynamics  Data processing, Vortex motion
 Format
 Document (PDF)
 Title
 Aerodynamic analysis of a propeller in a turbulent boundary layer flow.
 Creator
 Lachowski, Felipe Ferreira., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

Simulating the exact chaotic turbulent flow field about any geometry is a dilemma between accuracy and computational resources, which has been continuously studied for just over a hundred years. This thesis is a complete walkthrough of the entire process utilized to approximate the flow ingested by a Seviktype rotor based on solutions to the Reynolds Averaged NavierStokes equations (RANS). The Multiple Reference Frame fluid model is utilized by the code of ANSYSFLUENT and results are...
Show moreSimulating the exact chaotic turbulent flow field about any geometry is a dilemma between accuracy and computational resources, which has been continuously studied for just over a hundred years. This thesis is a complete walkthrough of the entire process utilized to approximate the flow ingested by a Seviktype rotor based on solutions to the Reynolds Averaged NavierStokes equations (RANS). The Multiple Reference Frame fluid model is utilized by the code of ANSYSFLUENT and results are validated by experimental wake data. Three open rotor configurations are studied including a uniform inflow and the rotor near a plate with and without a thick boundary layer. Furthermore, observations are made to determine the variation in velocity profiles of the ingested turbulent flow due to varying flow conditions.
Show less  Date Issued
 2013
 PURL
 http://purl.flvc.org/fcla/dt/3360798
 Subject Headings
 Acoustical engineering, Boundary layer control, Multiphase flow, Mathematical models, Fluid mechanics, Mathematical models, Turbulence, Mathematical models, Computatioinal fluid dynamics
 Format
 Document (PDF)