Isotropic Free-stream Turbulence Promotes Anisotropy in a Turbulent Boundary Layer

Abstract

The study of how external conditions affect turbulent boundary layers is important since such effects are often present in common engineering applications. Earlier investigations on surface roughness have shown its effect on the mean velocity and Reynolds stress profiles. Similarly, the effects of free-stream turbulence have been well documented [1, 2, 3]. However, the results available until now are limited to low Reynolds numbers. Hence, the aim of this investigation is to study the effects of high free-stream turbulence on rough surface turbulent boundary layers, at relatively high Reynolds numbers. This investigation focused on the penetration mechanisms of free-stream turbulence into the boundary layer, identifying the length scales that dominate these mechanisms and studying the effects on the resulting turbulence anisotropy [4]. These effects will also be studied in turbulent boundary layers subject to favorable pressure gradients.KeywordsBoundary LayerReynolds StressTurbulent Boundary LayerIsotropic TurbulenceFavorable Pressure GradientThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.