V形前缘对激波入射边界层流动影响的数值模拟与分析

Numerical Studies on Effects of V-Shaped Leading Edge on Incident Shock Wave Boundary Layer Interaction

关键词:  激波边界层干扰  V形前缘  高超声速进气道  流动分离  激波干扰

Key words:  Shock wave boundary layer interaction  V-shaped leading edge  Hypersonic inlet  Flow separation  Shock interaction

摘要:

为指导V形溢流唇口下游的进气道内部流动分析，采用数值模拟开展V形尖前缘对二维斜激波入射平板边界层流动的影响研究。以气流偏转角6°的二元楔面为基准激波发生器，设计了展向气流收缩角α(0°~60°, 0°对应二元构型)的V形前缘构型，开展对比研究。结果表明，V形前缘构型使得激波入射位置沿展向不均匀、流动具有明显三维特征，并且干扰区壁面压强上升、分离区尺度明显增大。在α=0°~60°范围内，干扰区流动的不均匀程度、分离区尺度随α增大单调增加。进一步分析表明，V形前缘构型干扰具有中间平直、侧边斜掠的耦合入射特性，体现为对称面壁面压强符合自由干扰理论，侧边斜掠入射区参数符合斜掠干扰的锥形流特征。对比二元与α=45°构型的无粘模拟结果，V形前缘会诱导展向两侧对称的斜掠激波、并在对称面相互干扰产生平直的“桥”激波，这使得激波入射位置沿展向不均匀并偏向下游。其中对称面处平直入射激波压升比(2.49)高于二元构型结果(2.24)，侧边斜掠激波强度与二元构型基本一致。这些因素综合导致V形前缘构型的分离尺度增大。

Abstract:

In order to instruct the internal flow analysis of hypersonic inlets with V- shaped spillage cowl edges, effects of V-shaped sharp leading edges (VsSLEs) on the incident interactions between oblique shock waves and flat plate boundary layers are investigated through numerical simulations. VsSLE shock generators, parameterized by spanwise swept angle α(0~60°), are designed based on a two- dimensional wedge with flow deflection angle of 6°. The results show that VsSLEs cause non-uniform incident interactions along the spanwise orientation, which induce three dimensional flows in the shock wave boundary layer interaction (SWBLI) regions. The wall surface pressures of VsSLE configurations are higher than those of the two dimensional configuration, and the scales of separated regions are also larger than those of the two dimensional case. The scales of separated regions increase monotonically as α increases within 60°. Further analysis show that the incident SWBLI of a VsSLE wedge is characterized by a flat incident interaction near the symmetry region and a swept incident interaction near the side region. The streamwise wall pressures of the symmetry surface accord well with free interaction theory and the flow parameters of the swept incident regions scales quai-conically. Comparing the inviscid flows of the two- dimensional and the VsSLE(α=45°) configurations, the VsSLE induce two symmetric swept shocks along the spanwise orientation, which interact with each other on the symmetrical plane and generate flat "bridge" shock. These cause the incident positions of the shocks non-uniform along the spanwise orientation and deviate downstream. The pressure rise ratio (2.49) of incident shock on the flat region of the VsSLE configuration is higher than that of the two dimensional configuration (2.24), while the intensity of swept shock is generally the same as that of the two dimensional configuration. These factors lead to the increase of the separation scales of VsSLE configurations.