Influence of surface roughness on anisotropy in a turbulent boundary layer flow

Keirsbulck, Laurent; Labraga, L.; Mazouz, A.; Tournier, C.

doi:10.1007/s00348-002-0424-9

Cited by 17 publications

(11 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast to these findings, Krogstad & Antonia (1994) claimed that roughness tends to reduce the overall anisotropy of the large-scale motion in a boundary layer with k-type rod roughness. This was supported by the measurements of the anisotropy tensor of Shafi & Antonia (1995) for a mesh surface and Keirsbulck et al (2002) for a rod-type roughness in a boundary layer. Djenidi, Elavarasan & Antonia (1999) investigated a boundary layer with d-type square rod roughness.…”

Section: Reynolds Stress Anisotropymentioning

confidence: 56%

An experimental and numerical study of channel flow with rough walls

et al. 2005

View full text Add to dashboard Cite

A fully turbulent channel flow with smooth and rod-roughened walls has been investigated using hot-wire anemometry and direct numerical simulations (DNS). The mean flow follows the law of the wall for both surfaces and the velocity defect suggests that the outer layer is very little affected by the roughness. The Reynolds stresses appear to be very similar for the two surface geometries outside $y\,{\approx}\,5k$, where $k$ is the roughness height. A quadrant analysis shows that the structural differences close to the wall extend somewhat further out. The turbulence structure is further investigated using stress ratios and the anisotropy tensor, which corroborate the findings from the Reynolds stresses. Many of the recent investigations on boundary layers seem to find large differences between smooth and rough wall data in the outer layer also. A tentative explanation for the apparent dependence on flow type of the surface roughness effects is given.

show abstract

Section: Reynolds Stress Anisotropymentioning

confidence: 56%

An experimental and numerical study of channel flow with rough walls

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Several previous experimental studies have shown that the introduction of surface roughness causes a reduction in the anisotropy tensor throughout the boundary layer (e.g. Krogstad & Antonia 1994;Shafi & Antonia 1995;Djenidi, Elavarasan & Antonia 1999;Antonia & Krogstad 2001;Keirsbulck et al 2002b). In a comparison of anisotropy tensors between smooth and rough walls using various previous experimental and numerical data, Smalley et al (2002) found that the magnitudes of b 11 , b 22 and b 33 for the rod-roughened wall are decreased more than those of the smooth wall in the outer layer.…”

Section: Reynolds Stressesmentioning

confidence: 96%

Direct numerical simulation of the turbulent boundary layer over a rod-roughened wall

2007

View full text Add to dashboard Cite

The effects of surface roughness on a spatially developing turbulent boundary layer (TBL) are investigated by performing direct numerical simulations of TBLs over rough and smooth walls. The Reynolds number based on the momentum thickness was varied in the range Reθ = 300 ∼ 1400. The roughness elements were periodically arranged two-dimensional spanwise rods, and the roughness height was k = 1.5θin, where θin is the momentum thickness at the inlet, which corresponds to k/δ = 0.045 ∼ 0.125, δ being the boundary layer thickness. To avoid generating a rough-wall inflow, which is prohibitively difficult, a step change from smooth to rough was placed 80θin downstream from the inlet. The spatially developing characteristics of the rough-wall TBL were examined. Along the streamwise direction, the friction velocity approached a constant value, and self-preserving forms of the turbulent Reynolds stress tensors were obtained. Introduction of the roughness elements affected the turbulent stress not only in the roughness sublayer but also in the outer layer. Despite the roughness-induced increase of the turbulent Reynolds stress tensors in the outer layer, the roughness had only a relatively small effect on the anisotropic Reynolds stress tensor in the outer layer. Inspection of the triple products of the velocity fluctuations revealed that introducing the roughness elements onto the smooth wall had a marked effect on vertical turbulent transport across the whole TBL. By contrast, good surface similarity in the outer layer was obtained for the third-order moments of the velocity fluctuations.

show abstract

“…Please note that the interchange of steeper and flatter regions in the reconstructed pdf is achieved by the piecewise linear parameterization of D (1) and D (2) . A second verification is the reconstruction of conditional pdf by direct numerical solution of the Fokker-Planck equation (5). An example for the scales r 0 = 188 mm and r 1 = 131 mm is shown in fig.…”

Section: Verification Of Coefficientsmentioning

confidence: 99%

Stochastic analysis of surface roughness

Waechter

Riess²,

Kantz³

et al. 2003

Europhys. Lett.

View full text Add to dashboard Cite

For the characterization of surface height profiles we present a new stochastic approach which is based on the theory of Markov processes. With this analysis we achieve a characterization of the complexity of the surface roughness by means of a Fokker-Planck or Langevin equation, providing the complete stochastic information of multiscale joint probabilities. The method was applied to different road surface profiles which were measured with high resolution. Evidence of Markov properties is shown. Estimations for the parameters of the Fokker-Planck equation are based on pure, parameter free data analysis.

show abstract

Influence of surface roughness on anisotropy in a turbulent boundary layer flow

Cited by 17 publications

References 6 publications

An experimental and numerical study of channel flow with rough walls

An experimental and numerical study of channel flow with rough walls

Direct numerical simulation of the turbulent boundary layer over a rod-roughened wall

Stochastic analysis of surface roughness

Contact Info

Product

Resources

About