Calculation of two-dimensional diffusers

A calclation procedure for two-dimensional diffusers in incompressible flows is described. It is assumed that the inflow is composed of a homogeneous frictionless core flow and the wall boundary layers. An improved current flow theory is presented which depends on the condition of constant cross sectional pressure and permits the flow quantities and the wall pressure in particular to be determined from the local behavior of the displacement thickness line. The diffuser characteristic quantities are presented, the improved theory is developed, and its accuracy is assessed. Illustrative calculations are performed which compare transitional and terminal diffusers and show the effect of smoothing in the inlet area and of Reynolds number on diffuser characteristic numbers and the flow separation.