Abstract
Our experimental study is devoted to the analysis of the flow past wto tandem circular cylinders near the vortex shedding threshold. A recent two-dimentional numerical analysis of this flow, Mizushima & Suehiro (2005), has predicted that the bifurcation diagram should becomes complex in the vicinity of the instability threshould. subcritical and saddle node bifurcation that lead to hysteretic exchanges between two different modes of vortex shedding were detected for particular distance of separation of the cylinders. We present here visualization and velocity profile measurement of this flow in a water channel to prove the robustness of the complexity of the bifurcation diagram in real flows and to clarify the three-dimentional effect due to finit length of the cylinders.
