In the study of flow oscillation and discrete frequency noise of impinging jet, it is found that there is a critical pressure ratio for a given nozzle and a nozzle-to-plate distance.

• 发现对于给定的喷嘴和冲击距离,存在一个压比临界点,当压比高于此临界点值时,流场振荡和离散频率噪声被显著抑制乃至消失。