超声速欠膨胀冲击射流流场振荡的数值模拟

为了研究超声速欠膨胀冲击射流自激振荡与喷嘴进出口压比的关系,对轴对称冲击射流进行了数值模拟,计算中采用了雷诺应力模型。结果发现:当喷嘴压比较小时,流场振荡随喷嘴压比的增大而加剧。当压比处于某一范围内时,流场振幅最大,振荡最剧烈。随着压比的继续增大,流场振幅又减小。流场振幅随喷嘴压比的变化与冲击单音强度随喷嘴进出口压比的变化相似,说明流场振荡与冲击单音有内在的关联。

Numerical simulation on flow field oscillation of under-expanded supersonic impinging jet

To investigate the relationship between the flow field oscillation of an under-expanded supersonic impinging jet with its nozzle pressure ratio (NPR), numerical simulation with the RSM model was applied to symmetrical impinging jet. The results show that the flow field oscillation is relevant to the NPR. The amplitude of the oscillation augments with the increasing NPR, which reaches its maximum on a critical pressure ratio. However, the amplitude reduces as the NPR goes on increasing. The variation of the flow field oscillation with the increasing NPR is similar to that of the impinging tone strength, which illuminates the impinging tone is correlative with the flow field oscillation.