助走管を有する先細ノズルにおける軸対称噴流の渦輪列の発生周波数とその活用

抄録

In this study, the frequency f_n at which the initial vortex train generated in the jet ejected by the converging nozzle with the entrance pipe was measured, and it was to clarify the determinants of f_n. The f_n at the Reynolds number Re = 1400 to 5600 was measured. As a result, the f_n was changed by changing the length of the entrance pipe, regardless of the same nozzle, the same flow velocity and measurement environment. Also, the f_n doesn’t increase linearly with Re, but it rises stepwise. In the simulation, organ pipe resonance inside the nozzle was evaluated. As a result, the resonance frequency was observed at a frequency that the f_n was became almost flat of rising stepwise with increasing Re. Therefore, it was found that the frequency of the organ pipe resonance determined by the shape of inside of the nozzle, dominates the f_n.