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为了研究激波与旁路转捩边界层的干扰机理,采用直接数值模拟(DNS)方法对来流马赫数Ma∞=2.9,24°压缩拐角内激波与转捩边界层的相互作用进行了系统的研究。考察了旁路转捩干扰下压缩拐角内分离区形态和激波波系结构的典型特征。比较了转捩干扰与湍流干扰流动结构的差异,并分析了造成差异的原因。研究了拐角内转捩边界层的演化特性,探讨了转捩干扰下脉动峰值压力和峰值摩阻的分布规律及形成机制。研究结果表明:相较于湍流干扰,两侧发卡涡串的展向挤压使得分离区起始点以V字型分布,且分离激波沿展向以破碎状态为主,激波脚呈现多层结构;拐角内的干扰作用急剧加速了边界层的转捩过程;转捩干扰下的拐角内峰值脉动压力以单峰结构出现在分离区的下游,同时干扰区内的强湍动能和高雷诺剪切应力使得其局部峰值摩阻系数要高于湍流干扰。
In order to study the interference mechanism between the shock wave and the bypass transition boundary layer, the direct numerical simulation (DNS) method was used to investigate the interaction between the shock wave and the transition boundary layer at Ma∞ = 2.9,24 ° System research. The typical characteristics of the shape of the separation zone and the structure of the shock wave system in the compression corner under the influence of bypass shunting were investigated. The differences between the turbulence-disturbing flow structure and the turbulent flow were compared, and the reasons for the differences were analyzed. The evolution of the boundary layer in the corner transition was studied, and the distribution and formation mechanism of the peak pressure and peak friction were discussed. The results show that compared with the turbulent disturbance, the vortex-induced extrusion of both sides of the hairpin vortex strings causes the starting point of the separation region to be distributed in a V shape, and the separation shocks are mainly in the crushing state along the span direction. The shock wave feet exhibit multiple layers Structure. The disturbance in the corner accelerates the transition of the boundary layer rapidly. The peak pressure fluctuates within the corner under the disturbance and appears as a single peak downstream of the separation zone. At the same time, the strong turbulent kinetic energy and the high Reynolds shear force Shear stress makes its local peak friction coefficient is higher than turbulent interference.