低レイノルズ数域における後方ステップ流れの制御に関する研究（安定性解析を利用したSynthetic jetによる再付着流れの制御）

概要

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The objective of the present paper is to perform the effective control by the periodic disturbance in a backward facing step in low Reynolds number range. At first, in order to clarify the overall characteristics of separating shear layer, the flow behavior of the transverse vortices in the main flow and a reattachment length on a lower side wall were investigated by Hot-wire anemometer and Micro Flow Sensor(MFS). The characteristic frequency of the flow fluctuation was estimated to be about 36 Hz from FFT analysis. The change of the upstream vortex structure affects the downstream periodic flow behavior. To identify the periodic flow, the frequency dominating the separating shear layer was analyzed by the linear stability theory. From this result, the periodic disturbance was given to separating flow by means of the synthetic jets from the upper wall. The effective forcing frequency of the synthetic jets was evaluated from the reattachment length on the lower wall and the flow behavior in the separating shear layer.