Flow around a pair of circular cylinders arranged side by side at high Reynolds numbers.

Abstract

Flow and aerodynamic characteristics of a pair of circular cylinders arranged side by side in a uniform flow were experimentally studied at high Reynolds numbers near and over the critical one. Pressure distributions, lift and drag coefficients and Strouhal numbers were measured at different spacings in a wind tunnel. There are good agreements between the present results and others at subcritical Reynolds numbers. At high Reynolds numbers over critical one, we examined the relationships among the formation of separation bubbles, the aspect of wakes, and the lift and drag coefficients. Separation bubbles are formed only on the outward sides of two cylinders at small spacings and this leads to a positive and significant increase in lift coefficient, and biased flow with a high Strouhal number like at subcritical Reynolds numbers cannot be observed to appear.