An Investigation of the Flow around a Permeable Three-dimensional Body on the Plate(2nd Report, Effect of the Variation of the Boundary Layer Thickness)

Measurements were made of the surface pressure and drag acting on the permeable cube model having a various open area ratio set into a flat plate turbulent boundary layer, and of the flow patterns and pressure distributions on the floor. Flow visualization also have been done using the oil film method. The relative height of the model with respect to the boundary layer thickness was chosen in the range of h/δ=0.289 to 2.857. The value of open area ratio β of model were varied for 0≦β≦0.456. The results showed that the strength of horse-shoe vortex surrounding the model was varied with changing the value of h/δ. The reversed flow region and arch-type vortex formation region moved upstream with increasing the value of h/δ, but moved downstream with increasing the value of β. A tendency of the drag coefficient evaluated from the pressure difference acting on both front and rear permeable walls showed an abrupt change at the value of β of about 0.25 to 0.35 for each value of h/δ.