Flow Around Two Intersecting Circular Cylinders

One aspect of the flow around two intersecting cylinders, which has attracted little attention so far, is the structure of a three-dimensional near-wake behind the intersection. Some preliminary measurements of pressure distributions along the span were complemented by oil-film surface flow visualization. A strong secondary flow was found in the near-wake which extended spanwise more than three diameters from the intersection. The main feature was the formation of four symmetrically positioned pairs of swirling vortices which originated from the surface of the cylinders. The secondary flow caused an increase in the local drag coefficient.