Vortex Wake Visualization of Two Parallel Cylinders in Staggered Arrangement

Abstract

The interacting vortex wakes of two circular cylinders in staggered arrangement are examined by visualization experiments using a towing water tank. The cylinder spacing parameters are expressed in terms of the stream-wise spacing ratio L/d (0 to 10.0) and the transverse spacing ratio T/d (0 to 4.0) for a fixed Reynolds number of 80. The point of the present study is the flow pattern analysis in various geometric arrangement of the two cylinders, covering a wide range of spacing para-meters, inclusive of the so-called bistable regime of vortex shedding, and the simultaneous measurement of Strouhal numbers corresponding to the wake frequency detected outside the near-wake region. Another point of the paper is the complicated vortex wake interaction and the subsequent wake evolution observed downstream of the leeward cylinder.