EXPERIMENTAL-STUDY OF SADDLE-POINT OF ATTACHMENT IN LAMINAR JUNCTURE FLOW

An experimental study of laminar horseshoe vortex flows upstream of a cylinder/flat plate juncture has been conducted to verify the existenc e of saddle-point-of-attachment topologies, In the classical depiction of this flowfield, a saddle point of separation exists on the flat pl ate upstream of the cylinder, and the boundary layer separates from th e surface, Recent computations have indicated that the topology may ac tually involve a saddle point of attachment on the surface and additio nal singular points in the how, Laser light sheet flow visualizations have been performed on the symmetry plane and crossflow planes to iden tify the saddle-point-of-attachment flowfields. The visualizations rev eal that saddle-point-of-attachment topologies occur over a range of R eynolds number in both single and multiple vortex regimes, An analysis of the flow topologies is presented that describes the existence and evolution of the singular points in the flowfield.