Flow Characteristics of Pulsating Flow Obstructed by an Array of Square Rods

Abstract

Abstract A series of flow visualization experiments of pulsating flow obstructed by an array of square rods was carried out to investigate its characteristics. When the pulsation is absent, Karman vortices shed periodically from each rod. When the pulsation period is relatively long compared with the shedding period and its amplitude is large, the flow is stabilized during the accelerating phase and, during the decelarating phase, the flow is destabilized and Karman vortices break down. When the pulsation period is shorter than shedding period and its amplitude is large, the flow pulsation controls the generation and breakdown of the Karman vortices. A numerical simulation code was developed and compared with the experimental results. When the pressure gradient parameter of the code is changed sinusoidally with time, computed results become the pulsating flow. Time variations of the streamwise pressure gradient and cross-sectional averaged velocity show similarity between the experimental and computed results.