リングを過ぎる流れの曲率効果と厚み効果(流体工学,流体機械)

概要

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The present aim is to clarify the combination effect of curvature and streamwise thickness of a ring with rectangular cross sections, which is immersed perpendicularly to uniform flow. In a wind tunnel, the authors carry out measurements using a pressure manometer and hot-wire anemometers, and flow visualisations by a smoke-wire method, for Re=5.0×10^3-1.5×10^4, d/w=3.0-16.0 and t/w=0.28-1.80, where Re, d, w and t are the Reynolds number, mean diameter, cross-section width and cross-section thickness of the ring, respectively. Consequently, the Strouhal number St, which is a reduced frequency of regular vortex shedding from the ring, is independent of d/w, t/w and Re. On the other hand, base suction depends not on Re, but on d/w and t/w. Considering d/w and t/w as governing parameters, and regarding to base suction, flow visualisation, velocity fluctuation, mean-velocity and turbulence-intensity profiles and four-points velocity correlation, we can classify flow into four flow modes; viz., an over-critical axisymmetrical mode, a sub-citical axisymmetrical mode, a sub-critical non-axisymmetrical mode and a sub-critical less-correlation mode.
一般社団法人日本機械学会の論文
2007-01-25