Asymmetrical boundary layer separation at the base of a two cylinder geometry

This paper reports on the experimental description of the three-dimensional horseshoe vortex system occurring at the base of two cylinder mounted side by side on an endwall. The spacing between the two cylinders is adjusted to generate a family of viscous flows. Flow visualization performed in a water tunnel provides a qualitative understanding of the flow over a range of flow variables. A detailed wind tunnel experiment provides a quantitative description of the flow at a single test condition. At Re(D) = 2.5 x 10 to the 5th the measurements show an asymmetrical primary vortex with a wide flat cross section. A small counterrotating vortex is found between the primary vortex and the cylinder leading edge.