Reverse flow in converging channels with obstruction at the entry

Abstract

Reverse flow in a parallel walled test channel placed in a wider channel is observed when an obstruction is placed at the test channel entry. When the position of the obstruction at the test channel entry is varied relative to the test channel, the flow inside the test channel reverses (opposite to the wider channel flow), stagnates or flows in the forward direction. The present study is to establish this unsteady flow, involving reverse flow in the converging channels for various g/w ratios at Re = 4000. The converging angles studied are 0.2°, 0.4°, 0.6°, 0.8° and 1.0°. The reverse flow magnitude increases as the convergence angle is increased till 0.6°, and then starts decreases when the convergence angle is further increased. The results also show us more insight about the reverse flow phenomenon and mechanism offluid pumping due to shear layer interaction at channel exit for the various convergence angles.