円管内を横切る円柱に働く抗力と放出渦

概要

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In order to investigate flow fields in vortex flow meters, we used a circular cylinder transverse in a pipe instead of a vortex -shedding bluff body. Then, time-averaged pressure distributions on the surface of the cylinder are measured, and fluctuating streamwise velocities are analyzed statistically. The contraction ratio β of a cylinder diameter to a pipe diameter varies between 0.102 and 0.510. The wall blockage of a pipe strongly influences the flow fields. Brief results are as follows. Drag coefficients and Strouhal numbers defined by the mean flow velocity are rapidly increased with β. However, the modified drag coefficients and modified Strouhal numbers, which are defined by the mean velocity through the minimum flow area in a pipe, are nearly equal to those in a two-dimensional uniform flow. Further, vortices shedding from a cylinder are aligned along the axis of a pipe.
1987-08-25