Behavior of Spherical Particles at Low Reynolds Numbers in a Fluctuating Translational Flow. Preliminary Experiments

摘要: The behavior of small spheres in non-steady translational flow has been studied experimentally' for values Reynolds nunber from 0 to 3000. aim the work was to improve our quantitative understanding of particle transport turbulent gaseous media, a process of extreme importance powerplants and energy transfer mechanisms. Particles, subjected strong sinusoidal oscillations parallel to direction steady translation, were found have changes in average drag coefficient depending upon their Reynolds number, frequency amplitude oscillations. When the Reynolds number based on sphere diameter les s than 200, the synunetric oscillation had negligible effect the aver age dr ago For numbers exceeding 300, effective coefficient was significantly increased particular range. For example, an increase 25 per cent observed at a nwnber 3000 when was 2 diazneter disturbance approximately the Strouhal frequency. occurrence maximum effect at frequencies between one two times Stroubal frequency strongly suggests non-linear interaction wake vortex shedding and motions. Flow visualization studies support this suggestion.