Side-by-side cylinders in crossflow with freestream turbulence

An experimental approach to examine the influence on freestream turbulence on the wakes issuing from a pair of side-by-side cylinders in crossflow is undertaken. These experiments are performed via particle image velocimetry in a closed loop wind tunnel. Both the ratio of transverse space to the diameter of the cylinder (T/D) as well as inflow turbulence intensity (Tu%) are varied in order to allow a thorough comparison of the changes due to freestream turbulence on differing canonical flow regimes. For each T/D chosen, a control case utilizing the ambient Tu% of the wind tunnel is measured and analyzed which is comparable to the low turbulence inflow conditions used in the literature to identify flow patterns that are characteristic of side-by-side cylinders in crossflow. Components of the time-averaged mean velocity and the time-averaged Reynolds stress tensor are compared in order to provide a detailed characterization of the similarities and differences between the flow fields in each of the twelve test cases. Proper orthogonal decomposition is also applied to identify relevant modes and organization in such flows.