Abstract
Turbulent flow measurements were conducted in the region between a pair of square cylinders set in uniform flow in tandem. The velocity data obtained with a PIV were averaged with respect to the pressure oscillation induced by vortex shedding from the cylinder to realize the three-level decomposition. The Reynolds stress related to the periodic fluid motion was found excessively large compared to those due to turbulent fluctuation. The correlation between the fluctuating pressure gradient and velocity was evaluated. The effect of organized vortex motion was recognized as the strong correlation between velocity and pressure gradient, which could explain the poor performance of RANS turbulence models in predicting this kind of flows.
