流れ方向に圧力こう配を有する二次元せん断流における粒子挙動の検討

概要

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Experiments were performed in a two-phase, streamwise pressure gradient plane mixing layer to study the behaviour of heavy particles in an intermittent shear flow. Velocity ratio was 0.377, and the high-speed side of inlet velocity was 10.5m/s. Two types of particles, 30 and 50μm glass spheres were fed into the low-speed stream. Particle and gas velocity statistics were obtained in flows subject to positive, neutral, and negative pressure gradient. These data, as well as flow visualization images, suggest that a negative pressure gradient rapidly develops particle organized motion induced by large-scale vortex. Streamwise pressure gradient does not affected to the ratio of the particle relaxation timeconstant and the large-scale eddy turnover time. Particle turbulent velocities show the similar profiles in these experiments. Transverse component of particle turbulent velocity in the mixing layer was observed to be 40% of the streamwise component. These data were well explained by the fact that particles have a response of about 63% for 100Hz velocity fluctuation and transverse velocity has little energy in these frequencies.
1991-06-25