Author: Stanford University. Thermosciences Division. Thermosciences Division
Publisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 388
Book Description
The Fluid Dynamics and Heat Transfer Effects of Streamwise Vortices Embedded in a Turbulent Boundary Layer
Author: Stanford University. Thermosciences Division. Thermosciences Division
Publisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 388
Book Description
Publisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 388
Book Description
The Fluid Dynamics and Heat Trnsfer Effects of Streamwise Vortices Embedded in a Turbulent Boundary Layer
Author: Wayne Robert Pauley
Publisher:
ISBN:
Category :
Languages : en
Pages : 343
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 343
Book Description
An Experimental Investigation of the Heat-transfer Effects of a Longitudinal Vortex Embedded in a Turbulent Boundary Layer
Author: Stanford University. Thermosciences Division. Thermosciences Division
Publisher:
ISBN:
Category :
Languages : en
Pages : 276
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 276
Book Description
The Effects of Streamwise Concave Curvature on Turbulent Boundary Layer Structure
Author: Albert H. Jeans
Publisher:
ISBN:
Category : Turbulent boundary layer
Languages : en
Pages : 176
Book Description
Concave curvature has a relatively large, unpredictable effect on turbulent boundary layers. Some, but not all previous studies suggest that a large-scale, stationary array of counter-rotating vortices exists within the turbulent boundary layer on a concave wall. The objective of the present study was to obtain a qualitative model of the flow field in order to increase our understanding of the underlying physics. A large free-surface water channel was constructed in order to perform a visual study of the flow. Streamwise components of mean velocity and turbulence intensity were measured using a hot film anemometer. The upstream boundary was spanwise uniform with a momentum thickness to radius of curvature of 0.05. Compared to flat wall flow, large-scale, randomly distributed sweeps and ejections were seen in the boundary layer on the concave wall. The sweeps appear to suppress the normal mechanism for turbulence production near the wall by inhibiting the bursting process. The ejections appear to enhance turbulence production in the outer layers as the low speed fluid convected from regions near the wall interacts with the higher speed fluid farther out. The large-scale structures did not occur at fixed spanwise locations, and could not be called roll cells or vortices. (Author).
Publisher:
ISBN:
Category : Turbulent boundary layer
Languages : en
Pages : 176
Book Description
Concave curvature has a relatively large, unpredictable effect on turbulent boundary layers. Some, but not all previous studies suggest that a large-scale, stationary array of counter-rotating vortices exists within the turbulent boundary layer on a concave wall. The objective of the present study was to obtain a qualitative model of the flow field in order to increase our understanding of the underlying physics. A large free-surface water channel was constructed in order to perform a visual study of the flow. Streamwise components of mean velocity and turbulence intensity were measured using a hot film anemometer. The upstream boundary was spanwise uniform with a momentum thickness to radius of curvature of 0.05. Compared to flat wall flow, large-scale, randomly distributed sweeps and ejections were seen in the boundary layer on the concave wall. The sweeps appear to suppress the normal mechanism for turbulence production near the wall by inhibiting the bursting process. The ejections appear to enhance turbulence production in the outer layers as the low speed fluid convected from regions near the wall interacts with the higher speed fluid farther out. The large-scale structures did not occur at fixed spanwise locations, and could not be called roll cells or vortices. (Author).
Numerical Simulation of Heat Transfer Enhancement Resulting from a Streamwise Vortex Embedded in Laminar and Turbulent Boundary Layer Flows
Author: David Shan-Ming Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 252
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 252
Book Description
Experimental Study of the Effect of Streamwise Vortices on Unsteady Turbulent Boundary-layer Separation
Author: W. W. Humphreys
Publisher:
ISBN:
Category :
Languages : en
Pages : 296
Book Description
This experiment studied the effect of streamwise vortices on unsteady turbulent boundary-layer separation. The objectives were to document the flow field, to characterize the time response of the boundary layer, and to understand the actual mechanisms by which the streamwise vortices modify boundary-layer behavior. A new configuration for non-obtrusive three-component Laser Doppler Anemometry (LDA) determined the phase averaged velocity and Reynolds stress components, in an unsteady water tunnel, at a momentum thickness Reynolds number of 1840. The streamwise vortices were created by three pairs of half-delta wing vortex generators, while the boundary-layer separation was controlled through impulsively initiated opposite-wall suction, which created a strong adverse pressure gradient. The time response of the freestream velocity demonstrates that convection is the primary mechanism by which vortex generators modify the response of the boundary layer. There is an initial fast response throughout the boundary layer which is unaffected by the presence of vortex generators, followed by a slow or convective response, the magnitude of which is substantially modified by the presence of the vortex generators. Flow control, Unsteady turbulent layers. Aircraft, Vortex generators. (jes).
Publisher:
ISBN:
Category :
Languages : en
Pages : 296
Book Description
This experiment studied the effect of streamwise vortices on unsteady turbulent boundary-layer separation. The objectives were to document the flow field, to characterize the time response of the boundary layer, and to understand the actual mechanisms by which the streamwise vortices modify boundary-layer behavior. A new configuration for non-obtrusive three-component Laser Doppler Anemometry (LDA) determined the phase averaged velocity and Reynolds stress components, in an unsteady water tunnel, at a momentum thickness Reynolds number of 1840. The streamwise vortices were created by three pairs of half-delta wing vortex generators, while the boundary-layer separation was controlled through impulsively initiated opposite-wall suction, which created a strong adverse pressure gradient. The time response of the freestream velocity demonstrates that convection is the primary mechanism by which vortex generators modify the response of the boundary layer. There is an initial fast response throughout the boundary layer which is unaffected by the presence of vortex generators, followed by a slow or convective response, the magnitude of which is substantially modified by the presence of the vortex generators. Flow control, Unsteady turbulent layers. Aircraft, Vortex generators. (jes).
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704
Book Description
Studies in Turbulence
Author: Thomas B. Gatski
Publisher: Springer Science & Business Media
ISBN: 1461227925
Category : Science
Languages : en
Pages : 609
Book Description
This book contains contributions by former students, colleagues and friends of Professor John L. Lumley, on the occasion of his 60th birthday, in recognition of his enormous impact on the advancement of turbulence research. A variety of experimental, computational and theoretical topics, including turbulence modeling, direct numerical simulations, compressible turbulence, turbulent shear flows, coherent structures and the Proper Orthogonal Decomposition are contained herein. The diversity and scope of these contributions are further acknowledgment of John Lumley's wide ranging influence in the field of turbulence. The large number of contributions by the authors, many of whom were participants in The Lumley Symposium: Recent Developments in Turbulence (held at ICASE, NASA Langley Research Center on November 12 & 13, 1990), has presented us with the unique opportu nity to select a few numerical and theoretical papers for inclusion in the journal Theoretical and Computational Fluid Dynamics for which Professor Lumley serves as Editor. Extended Abstracts of these pa pers are included in this volume and are appropriately marked. The special issue of TCFD will appear this year and will serve as an additional tribute to John Lumley. As is usually the case, the efforts of others have significantly eased our tasks. We would like to express our deep appreciation to Drs. R.
Publisher: Springer Science & Business Media
ISBN: 1461227925
Category : Science
Languages : en
Pages : 609
Book Description
This book contains contributions by former students, colleagues and friends of Professor John L. Lumley, on the occasion of his 60th birthday, in recognition of his enormous impact on the advancement of turbulence research. A variety of experimental, computational and theoretical topics, including turbulence modeling, direct numerical simulations, compressible turbulence, turbulent shear flows, coherent structures and the Proper Orthogonal Decomposition are contained herein. The diversity and scope of these contributions are further acknowledgment of John Lumley's wide ranging influence in the field of turbulence. The large number of contributions by the authors, many of whom were participants in The Lumley Symposium: Recent Developments in Turbulence (held at ICASE, NASA Langley Research Center on November 12 & 13, 1990), has presented us with the unique opportu nity to select a few numerical and theoretical papers for inclusion in the journal Theoretical and Computational Fluid Dynamics for which Professor Lumley serves as Editor. Extended Abstracts of these pa pers are included in this volume and are appropriately marked. The special issue of TCFD will appear this year and will serve as an additional tribute to John Lumley. As is usually the case, the efforts of others have significantly eased our tasks. We would like to express our deep appreciation to Drs. R.
Transport Phenomena in Heat and Mass Transfer
Author: J.A. Reizes
Publisher: Elsevier
ISBN: 0444599797
Category : Technology & Engineering
Languages : en
Pages : 833
Book Description
Theoretical, numerical and experimental studies of transport phenomena in heat and mass transfer are reported in depth in this volume. Papers are presented which review and discuss the most recent developments in areas such as: Mass transfer; Cooling of electronic components; Phase change processes; Instrumentation techniques; Numerical methods; Heat transfer in rotating machinery; Hypersonic flows; and Industrial applications. Bringing together the experience of specialists in these fields, the volume will be of interest to researchers and practising engineers who wish to enhance their knowledge in these rapidly developing areas.
Publisher: Elsevier
ISBN: 0444599797
Category : Technology & Engineering
Languages : en
Pages : 833
Book Description
Theoretical, numerical and experimental studies of transport phenomena in heat and mass transfer are reported in depth in this volume. Papers are presented which review and discuss the most recent developments in areas such as: Mass transfer; Cooling of electronic components; Phase change processes; Instrumentation techniques; Numerical methods; Heat transfer in rotating machinery; Hypersonic flows; and Industrial applications. Bringing together the experience of specialists in these fields, the volume will be of interest to researchers and practising engineers who wish to enhance their knowledge in these rapidly developing areas.
Applied mechanics reviews
Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 400
Book Description
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 400
Book Description