A New Rough Wall Layer Modeling Using the Brinkman Equation in Turbulent Boundary Layers

2008 ◽  
Author(s):  
Meng-Huang Lu ◽  
William Liou
Keyword(s):  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Wall Layer ◽  
Rough Wall ◽  
Brinkman Equation

scholarly journals Wall-drag measurements of smooth- and rough-wall turbulent boundary layers using a floating element

2016 ◽  
Vol 57 (5) ◽  
Author(s):  
W. J. Baars ◽  
D. T. Squire ◽  
K. M. Talluru ◽  
M. R. Abbassi ◽  
N. Hutchins ◽  
...  
Keyword(s):  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Rough Wall ◽  
Floating Element

Structure of rough-wall turbulent boundary layers

1988 ◽  
Vol 31 (7) ◽  
pp. 1877 ◽  
Author(s):  
Promode R. Bandyopadhyay ◽  
Ralph D. Watson
Keyword(s):  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Rough Wall

Turbulent boundary layers on a systematically varied rough wall

2009 ◽  
Vol 21 (1) ◽  
pp. 015104 ◽  
Author(s):  
Michael P. Schultz ◽  
Karen A. Flack
Keyword(s):  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Rough Wall

Studying turbulence using direct numerical simulation: 1987 Center for Turbulence Research NASA Ames/Stanford Summer Programme

1988 ◽  
Vol 190 ◽  
pp. 375-392 ◽  
Author(s):  
J. C. R. Hunt
Keyword(s):  
Boundary Layers ◽  
Turbulent Flows ◽  
Large Scale ◽  
Isotropic Turbulence ◽  
Stokes Equations ◽  
Turbulent Boundary Layers ◽  
Finite Amplitude ◽  
Wall Layer ◽  
Navier Stokes ◽  
Scale Motion

This paper is an account of a summer programme for the study of the ideas and models of turbulent flows, using the results of direct numerical stimulations of the Navier-Stokes equations. These results had been obtained on the computers and stored as accessible databases at the Center for Turbulence Research (CTR) of NASA Ames Research Center and Stanford University. At this first summer programme, some 32 visiting researchers joined those at the CTR to test hypotheses and models in five aspects of turbulence research: turbulence decomposition, bifurcation and chaos; two-point closure (or k-space) modelling; structure of turbulent boundary layers; Reynolds-stress modelling; scalar transport and reacting flows.A number of new results emerged including: computation of space and space-time correlations in isotropic turbulence can be related to each other and modelled in terms of the advection of small scales by large-scale motion; the wall layer in turbulent boundary layers is dominated by shear layers which protrude into the outer layers, and have long lifetimes; some aspects of the ejection mechanism for these layers can be described in terms of the two-dimensional finite-amplitude Navier-Stokes solutions; a self-similar form of the two-point, cross-correlation data of the turbulence in boundary layers (when normalized by the r.m.s. value at the furthest point from the wall) shows how both the blocking of eddies by the wall and straining by the mean shear control the lengthscales; the intercomponent transfer (pressure-strain) is highly localized in space, usually in regions of concentrated vorticity; conditioned pressure gradients are linear in the conditioning of velocity and independent of vorticity in homogeneous shear flow; some features of coherent structures in the boundary layer are similar to experimental measurements of structures in mixing-layers, jets and wakes.The availability of comprehensive velocity and pressure data certainly helps the investigation of concepts and models. But a striking feature of the summer programme was the diversity of interpretation of the same computed velocity fields. There are few signs of any convergence in turbulence research! But with new computational facilities the divergent approaches can at least be related to each other.

Rough-Wall Turbulent Boundary Layers

1991 ◽  
Vol 44 (1) ◽  
pp. 1-25 ◽  
Author(s):  
M. R. Raupach ◽  
R. A. Antonia ◽  
S. Rajagopalan
Keyword(s):  
Boundary Layers ◽  
Strong Support ◽  
Reynolds Numbers ◽  
Viscous Sublayer ◽  
Turbulent Boundary Layers ◽  
Rough Wall ◽  
Roughness Sublayer ◽  
Turbulence Structure ◽  
Wall Boundary ◽  
High Reynolds

This review considers theoretical and experimental knowledge of rough-wall turbulent boundary layers, drawing from both laboratory and atmospheric data. The former apply mainly to the region above the roughness sublayer (in which the roughness has a direct dynamical influence) whereas the latter resolve the structure of the roughness sublayer in some detail. Topics considered include the drag properties of rough surfaces as functions of the roughness geometry, the mean and turbulent velocity fields above the roughness sublayer, the properties of the flow close to and within the roughness canopy, and the nature of the organized motion in rough-wall boundary layers. Overall, there is strong support for the hypothesis of wall similarity: At sufficiently high Reynolds numbers, rough-wall and smooth-wall boundary layers have the same turbulence structure above the roughness (or viscous) sublayer, scaling with height, boundary-layer thickness, and friction velocity.

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