非对称来流下隔离段内激波串受迫振荡流动实验研究

为探讨超燃冲压发动机隔离段内激波串受迫振荡区域壁面压力脉动特性,用非对称马赫数1.98的隔离段直连实验研究了低频周期性的脉动反压对隔离段内流动的影响.实验结果表明:隔离段能有效地隔离周期性反压脉动对上游未扰动流场的影响;反压脉动以第二特征波速向上游传播并影响了上游的壁面压力脉动,但在激波振荡区域,压力脉动主要受激波振荡的影响;厚附面层一侧的下壁面激波振荡区域内压力脉动前传时以指数规律衰减;薄附面层的上壁面激波振荡区域内压力脉动前传时却是波动的.

EXPERIMENTAL STUDY OF FORCED SHOCK TRAIN OSCILLATION IN ISOLATOR UNDER ASYMMETRIC INCOMING FLOW

To analyze the response of the wall pressure fluctuation in an isolator when the shock train is subjected to a periodic motion at a low frequency, the isolator experiment is conducted in a blow-down supersonic wind tunnel at free stream Mach number of 1.98 under asymmetric incoming flow. Experimental results show that: The isolator effectively isolates the periodic back pressure fluctuation from affecting upstream undisturbed flow; The wall pressure fluctuations are due to the propagation of wave fronts with the second acoustic mode, but they are subjected to an oscillating shock train in the most part of the shock oscillation region; The attenuation of wall pressure fluctuations on the lower wall with thick boundary layer accords with the exponential law, but it fluctuates on the upper wall with thin boundary layer in the shock oscillation region.