Influence of High Freestream Turbulence on Smooth, Favorable Pressure Gradient Turbulent Boundary Layers

ORAL

Abstract

Experiments were conducted at the Corrsin Wind Tunnel at The Johns Hopkins University to understand the effects of high freestream turbulence on a smooth, favorable pressure gradient turbulent boundary layer. Freestream turbulence (\textit{Tu}$\le $6{\%}) was generated using an active grid, and values of \textit{Re}$_{\theta }\le $2570 were obtained. Measurements of the streamwise and wall-normal components of the mean velocity deficit and Reynolds stresses have been performed using Laser Doppler Anemometry. It is shown than none of the existing scales are able to collapse the mean velocity profiles and strong evidence of multiple scales is observed. Furthermore, a reduction in the wake region caused a decrease in the mean velocity gradient near the edge of the boundary layer. Moreover, turbulence production will be evaluated to study if this is the cause of an increase in the Reynolds stresses. It is also found that high freestream turbulence causes the skin friction to increase due to a higher velocity gradient at the wall.

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Authors

  • Jose Lebron-Bosques

    Rensselaer Polytechnic Institute

  • Sheilla Torres-Nieves

    Rensselaer Polytechnic Institute

  • Brian Brzek

    R.P.I., Rensselaer Polytechnic Institute

  • Luciano Castillo

    R.P.I., Rensselaer Polytechnic Institute

  • Raul Bayoan Cal

    The Johns Hopkins University

  • Charles Meneveau

    Johns Hopkins University, Johns Hopkins University, Baltimore, US, Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD, 21218, Dep. of Mechanical Engineering, Johns Hopkins University, The Johns Hopkins University