Minor Losses Due to Flow Through a Rounded Sudden Expansion

Experiments on steady flow through a nominally 2-D exit geometry with rounded edges are presented. The minor loss coefficient, K, can be greater than unity for sudden expansions with non-uniform velocity profiles. Pressure recovery due to deceleration of the exiting flow before it detaches results in conversion of kinetic energy to flow energy and a reduced the value of K. It is shown that K is a function of the dimensionless edge radius and the Reynolds number. Substantial pressure recovery is reported at large Re for r/h < 1.