Attenuation of wall-normal velocity statistics in a turbulent boundary layer by a passive perforated surface

Abstract: This study investigates the potential of a perforated surface with a subsurface chamber for the control of the turbulent boundary layer. The effect of the perforated surface on the turbulent statistics is investigated by single and cross-wire anemometry and particle image velocimetry. These experiments, for the first time, indicate the impact of the perforated surface on the statistics of the wall-normal velocity fluctuations and the Reynolds shear stress. It is found that the wall-normal velocity fluctuations are reduced above the perforated surface leading to a reduction in the Reynolds shear stress by up to 20% at its peak. It is shown that this reduction in the Reynolds shear stress is correlated with up to 12% reduction of the turbulent component of skin-friction drag coefficient. Keywords: boundary layer flow, turbulence, skin-friction drag