菱形角柱群管路内でのポケット部の有無による流れの変化(流体工学,流体機械)  [in Japanese] Effects of Wall Concavity on Oscillations of Jet Streams from Diamond-Shaped Cylinder Bundles(Fluids Engineering)  [in Japanese]

The promotion of jet-stream diffusion may enhance the efficiency of mechanical performance in various industrial devices such as fluid machinery and combustion equipments. Both active and passive means were applied for the control of jet streams. Our previous studies disclosed that diamond-shaped cylinder bundles produce a self-excited oscillating jet-stream flow field having multiple uniform flow-rate groups. The present visualization work deals with flip-flop flow oscillation from a diamond-shaped cylinder bundle with wall concavity. It is disclosed that the wall concavity has induced a substantial change in the flow patterns in the exit jet-stream field with strong turbulence and jet-stream dispersion.