A conceptually new analytic criteria for detection of fluid flow separation in general multidimensional, steady and unsteady, compressible and incompressible flow situations has been introduced, verified and generalized. The new formulation offers new possibilities for the inverse design of aerodynamic shapes when flow separatin should be prevented over a range of operating conditions. Specifically, the generalized analytic formulation can be easily used to check the reliability of any specified surface pressure variation. Furthermore, it can be used for the derivation of analytic expressions for families of acceptable surface pressure variations to be used in inverse design of aerodynamic configurations.
