Interactive separation from a fixed wall

Numerically a solution is sought to describe the separation process from a fixed wall in the interaction region. Introduction of an analytical flow velocity in the external flow insures continuity, irrotationality and the correct asymptotic behavior. In the boundary layer flow region, a finite difference procedure is employed. This procedure solves diffusion of vorticity rather than of momentum. It retains the full boundary layer equation in the region of reversed flow. The entire boundary layer flow region is mapped onto a finite computational domain in order to eliminate artificial cut-offs. Interactively, the external and boundary layer flows must agree on both boundary layer pressure distribution and displacement effects. This agreement is here achieved by least square minimization of the differences. Preliminary results seem a significant step forward for both accuracy and computational efficiency and flexibility. But though the boundary layer flow results do extend further downstream than previous work by a factor of two, the objective of a solution extending all the way downstream to infinity has not yet been met. In contrast, far upstream the scheme performs excellently.