On the application of suction for the stabilization of crossflow instability over perforated walls

Summary

Experimental investigations to study the control of crossflow instability in three-dimensional boundary layers with the aid of suction through perforated walls are presented. It is shown that suction can be a powerful tool to stabilize boundary layer flows that are subject to crossflow instability. To elucidate possible improvements, two different suction devices, which differ in the hole diameter of the perforated metal sheet, are used inside a swept flat plate. Stationary and travelling modes have a high receptivity to roughness and suction at their neutral stability point, hence we pay special attention to the chordwise position where the suction is applied. In particular, suction within the stagnation area can lead to an undesired increase of the disturbance content due to a spatial non-uniformity in the suction velocity. The suction device with larger holes in the perforated metal sheet leads to more homogeneous suction velocities and therefore to a significant damping of the travelling modes.