Reverse flow in channel-influence of obstruction geometry

In the present study the flow through and around a parallel walled channel with various obstruction geometries placed at the channel entry is investigated. The flow inside the channel is found to be either stagnant, reverse, or in the forward direction depending upon the position of the obstruction. Experiments were carried out with various obstruction geometries like square, triangular, circular and semi-circular to study the effect of the shape of the geometry on the reverse flow phenomenon. Of the four, the triangular geometry gave the maximum reverse flow. The square and the semi-circular gave almost the same as the flat plate. The maximum forward flow also depends upon the shape of the obstruction geometry. To study the effect of the afterbody length the rectangular shape was chosen and models of different afterbody lengths were investigated. It is seen that the shorter afterbody lengths give a higher reverse flow. The maximum forward flow velocity however is higher for larger afterbody lengths. © 1993 Springer-Verlag.