On interference between two circular cylinders at supercritical Reynolds number

The results of investigation of interference between two identical parallel circular cylinders carried out in a uniform smooth flow at supercritical Reynolds number (4.5 x 10(5)), by means of pressure distribution measurement in wind-tunnel testing, are presented and discussed. The results show that the characteristics of interference are completely different with those at subcritical Reynolds number due to the difference of wake structure behind cylinders. The flow around two cylinders in tandem arrangement, which is somewhat like the case of subcritical Reynolds number, may be classified into two distinct regimes and four patterns of pressure distribution. On the other hand, two distinct regimes and three types of pressure patterns may be identified in side-by-side arrangement. The abrupt changes in pressure distributions on both cylinders were observed in the special case of two cylinders in staggered arrangement. In general, the significant effect of interference between two circular cylinders at supercritical Reynolds number is restricted to be within a rather small spacing ratio (N/d = 1.7), except for two cylinders in tandem arrangement and its vicinity.