Transpiration cooling and the effects of pressure fluctuations beneath a turbulent boundary layer

The study of the pressure fluctuations beneath a turbulent boundary layer passing over a transpiration region is considered. For constant wall blowing, the power spectral density of the turbulence-induced pressure fluctuations at the wall can be characterized by low-order analytical models such as the Liepmann model. We show that the pressure fluctuations at the wall modulate the flow through the porous media and the fluctuating porous media flow is influenced by the porosity, permeability and other geometric characteristics of the porous structure. The effect of the pressure-velocity coupling at the interface of the transpiration wall and turbulent boundary layer flow is presented and the effects on the turbulence statistics are quantified.