Flow past two tandem cylinders with a slight misalignment angle between them

Abstract

This paper investigates the flow past two tandem cylinders with a slight misalignment angle between them. Unlike previous studies of flow past two parallel cylinders, the two cylinders are not on a same plane as the downstream cylinder is rotated slightly along an axis that is in the flow direction. Simulations are conducted for a cylinder length equal to 100 diameters, Reynolds numbers of 100 and 500 and the gap ratios of 0.5, 1, 2 and 4. If Re=100 and the gap ratio is 0.5, 1 and 2, intermittent vortex dislocation occurs, but the location of vortex dislocation varies between 15 and 35 diameters from the midsection. At gap ratios of 1 and 2, another vortex dislocation always occurs at the midsection because there is not vortex shedding at this location. This vortex dislocation at the midsection was not observed at Re=500 because there is vortex shedding at this position. The sectional drag coefficients of the two cylinders are nearly the same as those of two parallel cylinders with the same staggered distance. The standard derivation of the sectional lift coefficients of two cylinders at a section near the cylinder centres is smaller than those of two parallel cylinders with the same staggered distance.