An Experimental Investigation of Flow Unsteadiness Generated by Transitory Stall In Plane-Wall Diffusers

The effects of flow unsteadiness introduced by transitory stall in plane-wall, subsonic diffusers have been investigated using air as the working fluid. The results indicate that diffuser flow unsteadiness is basically a low frequency phenomenon which appears to be a direct function of time varying stall blockage in the diffuser. Quantitative correlation of unsteadiness as a function of geometry indicates that diffuser unsteadiness behaves systematically and that a geometric region of maximum unsteadiness is definable.