Self-induced vibration due to upward plane jet colliding with liquid surface. Vibration mechanism of jet flutter

When there are free liquid surface and jet or circulating flow in a vessel, sometimes the self-induced vibration of the liquid surface occurs according to the condition. The typical self-induced vibration of jet-liquid surface system is the phenomena that the upward plane jet colliding with the liquid surface causes when it is at the position partitioning the middle of a rectangular tank. There are two kinds, self-induced fluctuation and jet flutter in these phenomena. The object of this study is the latter, and it has been known that the frequency of this phenomenon coincides with that of the liquid surface vibration in a continuous tank which is partitioned at jet position and connected only near jet inflow port, and it occurs when jet velocity exceeds the limit value determined by the distance between the jet inflow port and liquid surface. The features of this phenomenon are explained. The measurement of the variable quantities, the constitution of the vibration system controlling frequency, the analysis of jet locus, the additional pressure on liquid surface by moving swell, exciting energy and the effect that various factors exert to excitation range are reported. (K.I.)