双垂直楔交叉激波与转捩边界层干扰

Crossing shock waves/transitional boundary layers interactions in the double vertical wedges configuration

针对超声速双垂直楔构型产生的交叉激波与转捩边界层干扰现象,结合风洞试验与数值模拟进行了深入研究。试验在中国空气动力研究与发展中心Φ600 mm脉冲燃烧风洞中开展,来流马赫数3.0,单位雷诺数2.1×10^(6)m^(-1),获得了流场纹影、壁面压力和壁面热流。结果表明:受交叉激波逆压梯度作用,层流边界层在激波交汇附近分离,并在干扰区迅速转捩;在上游安装斜坡型涡流发生器或粗糙带,诱导边界层在干扰前转捩为湍流,分离区被有效抑制,干扰区热流明显下降(热流峰值下降超过25%)。数值模拟和风洞试验得到的激波结构、壁面压力吻合良好,但壁面热流计算值明显大于试验值。对比转捩模型和湍流模型计算结果发现:明显偏高的湍流黏性系数是RANS方法在非分离区过高预测干扰区热流的主要原因。

Study on crossing shock waves/transitional boundary layer interaction in the double vertical wedges configuration was carried out using wind tunnel tests and numerical calculations.The wind tunnel tests were carried out atΦ600 mm pulse combustion wind tunnel.The Mach number of the free stream condition is 3.0,and the unit Reynolds number is 2.1×10^(6) m^(−1).The schlieren images,wall pressure and wall heat fluxes were obtained during the tests.The results show that because of the adverse pressure gradient caused by the crossing shock waves,the separation of the laminar boundary layer was captured near the shock waves intersection point.And the transition from laminar to turbulent occurred rapidly in the interaction region.After installation of vertex generator devices or roughness devices,the boundary layer transition position moved to the upstream of the interaction region,the separation was effectively inhibited.And the heat fluxes in the interaction region declined obviously.The peak value of heat fluxes was reduced by more than 25%.The shock wave structures and wall pressure distributions obtained from tests and simulations agreed well,while the prediction heat fluxes were much larger than the test results.The comparison between the calculated results of the transition model and the turbulence model shows that the obviously larger turbulence viscosity is the main reason why RANS methods over-predict the heat fluxes in the unseparated interaction region.