非定常运动下的激波/边界层干扰分离特性研究

Unsteady shock/boundary layer interaction of compression corner at movement conditions

采用高精度数值方法求解非定常雷诺平均N-S方程和单自由度强迫俯仰运动方程,研究二维压缩拐角模型在等速抬头/低头和周期性俯仰振动等运动方式下的非定常激波/边界层干扰问题,考察角速度、振幅和频率等参数对分离区非定常变化规律的影响。结果表明,压缩拐角等速抬头运动时分离区减小、等速低头运动时分离区增大,周期性俯仰振动时分离点、再附点以及分离区大小的变化都与模型振动频率相同。与相同来流条件下定姿态计算对比分析表明,压缩拐角壁面运动产生的非定常迟滞作用使分离区大小变化减慢,俯仰振动振幅对分离区大小变化影响较大、而对变化的相位影响较小,而振动频率的改变对分离区大小变化的相位影响很大、对分离区大小影响较小。

Unsteady shock/boundary layer interaction generated by 2-D compression corner under move-ment conditions is studied by numerical calculating the unsteady Reynolds averaged N-S equations,and the unsteady characteristics of separation zone during the process of pitching up,pitching down and periodically oscillating are analyzed.The numerical results show that when the model pitches up,the size of separation region becomes smaller,and when the model pitches down,the size of separation region becomes larger. The positions of separation points,reattachment points and shock oscillate periodically as the oscillation of the compression corner and the frequency of the oscillation agrees with each other.When the amplitude of model increases,the change of separation region becomes wider.When the frequency of model increases,the position of the maximal and minimal separation region is distinctly changed during the oscillation of compres-sion corner.Furthermore,the results are compared to those calculated at static conditions,and conclusion is achieved that the variation of separation region is dominated by both of the pitching angle and the unsteady movement effects.Changing of pitching angel leads to the change of free stream Mach number,which have influence on the separation flow.