Three-dimensional flow past two cylinders mounted side by side on an endwall

This paper reports on the experimental description of flow past two cylinders that stand side by side on an endwall. The spacing between the two cylinders is adjusted to generate a family of viscous flows that are highly three-dimensional in nature. An asymmetrical horseshoe vortex system is formed around the base of each of the cylinders. Flow visualization performed in a water tunnel provides a qualitative understanding of the three-dimensional flow over a range of control variables. A quantitative description of the flow is obtained from a wind tunnel experiment. Limiting streamline flow visualization shows the streamline topology on the endwall and cylinder surfaces. The endwall flow visualization shows the location of the three-dimensional separation for a range of cylinder spacings. For a cylinder spacing of 1 . 5 diameters between centers, the flow is described by the use of a five hole probe and by cylinder and endwall surface static pressure measurements. At a cylinder diameter Reynolds number of 2.5 x 10' the measurements show a single primary vortex with a wide flat cross section. The velocity measurements show high shear on the endwall in the primary vortex region. A small counter rotating Gortex is found between the primary vortex and the cylinder leading edge.