Single component LDV (Laser Doppler Velocimetry) measurements were obtained in the separated 2D thin laminar boundary layer over an elliptic cylinder. The ellipse had an axis ratio of 4:1 and the incoming Reynolds numbers based on the minor axis were 675 and 1350. Velocity measurements were obtained within 0.05 mm from the surface both in attached and reverse flow regions. Painting the model with matt black paint and covering the tunnel walls proved to be effective means of improving signal quality. Measurements were successful both in back and forward scatter modes. The velocity profiles measured with Bragg cells indicate that the flow is separated at the ellipse mid-chord and that the separation bubble extends far downstream in the wake. The velocity profiles in the attached flow region compare well with the results of a boundary layer computation.

An experimental investigation of the three dimensional laminar boundary layer separation associated with an incident swept shock wave was conducted in the von Karman Institute (VKI) S-1 supersonic wind tunnel operating at Mach 2.15. Mean velocity profiles were measured both in the attached separated and reattachment flow regions using a laser doppler velocimeter. A comparison of the measurements with a full 3D Navier-Stokes solver, developed at the VKI, exhibited good agreement in all three regions, thus validating the code which was based on the Beam-Warming algorithm. The report also reviews the earlier parts of the grant dealing with the necessary developments in LDV to achieve high quality data, and the of the 2D shock boundary layer interaction. Keywords: Two dimensional flow; Three dimensional flow; Laminar boundary layer; Flow separation.