A Suction Scheme Applied to Flow Through Sudden Enlargement

Abstract

This paper describes an experimental study of the incompressible flow through a step expansion in a circular pipe as affected by suction through an annular gap lining the convex corner of the step. A uniform inlet flow with thin boundary layer is considered. Application of suction at a rate greater than some critical value caused the flow to expand rapidly into the larger diameter (basic effect previously termed an “edge suction effect”), the degree of expansion greatly dependent on gap orientation and size. Critical suction rates have been determined and other data collected to evaluate the configuration as a (short) diffuser.