S0502-4-3 筒状物体を過ぎる高レイノルズ数流れ([S0502-4]噴流,後流および剥離流れ現象の解明と制御(4))

概要

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The present aim is to reveal the flow past a pipe which is immersed parallel to the mainstream at high Reynolds numbers. In a wind tunnel, we carry out (1) base-pressure measurements, (2) velocity-fluctuation measurements using a hot-wire anemometer and (3) flow visualisations by a smoke-wire method with PIV analyses. The tested parameter ranges are Re = 2.0×10^3-1.3×10^4, d/t=4.0-10.0 and l/t=1.0-10.0, where Re, d, t and l are the Reynolds number, mean diameter, thickness and length of the pipe, respectively. As a result, the Re effects are negligible. The base-suction coefficient -C_<pb> monotonously decreases with increasing l/t, or with decreasing d/t. In addition, we conduct flow visualisations, and reveal the effects upon axisymmetry of wake. Finally, we classify the flow into three modes based on both periodicity and axisymmetry.
2010-09-04