Fluctuating fluid forces acting on two circular cylinders in a tandem arrangement at a subcritical Reynolds number

Aerodynamic characteristics of two circular cylinders in a tandem arrangement were investigated experimentally in a uniform flow at a Reynolds number of 6.5×104. This Reynolds number is within the range in which fluid forces acting on a single cylinder are comparatively insensitive to change in the Reynolds number. Mutual interference between the two cylinders at close proximity, however, caused significant change in parameters of the aerodynamic characteristics, such as fluctuating lift and drag forces, time-averaged and fluctuating pressure distributions, Strouhal number, and vortex-shedding patterns, when the spacing between the cylinders was changed. The changes in these aerodynamic characteristics were systematically analyzed in this study.