基于γ-Reθ转捩模型的高超声速复杂构型转捩模拟

Hypersonic boundary layer transition simulation of complex configuration using γ-Re_θ transition model

在大规模并行可压缩Navier-Stokes求解器AHL3D框架上,搭建了γ-Reθ转捩模型。在该模型基础上,通过高超声速二维进气道构型算例,加入了可压缩性修正,使其能够模拟可压缩性对转捩位置的影响,同时通过修改分离诱导转捩关键参数,增加了模型对粗糙颗粒诱导强制转捩的敏感性,最后对耦合关系式也进行了适当的修改。为了验证修改后的模型对高超声速自然转捩和强制转捩的预测能力,对Ma7.4Ames全尺寸模型和单个粗糙颗粒诱导Ma6的平板转捩进行了模拟。结果表明:与原始模型相比,修改后的模型的转捩位置被大大推迟,并且粗糙颗粒诱导转捩的作用被加强,与实验结果吻合良好。采用此模型对X-51A的20%缩比进气道模型在普渡大学Ma6静音风洞中的试验状态进行了模拟,模型不仅能够反映来流湍流度对转捩的影响,也能反映转捩带对转捩的促进作用。结果显示修改的转捩模型在高超声速复杂构型的转捩预测及研究中具有很好的应用潜力。

The correlation-basedγ-Reθtransition model has been implemented into a large scale parallel compressible Navier-Stokes solver AHL3D.In order to simulate the effects of compressibility of the hypersonic flow,compressible modification has been added into this model.The constant parameter for the separation induced transition has been enhanced to improve the ability of the forced transition simulation.The correlation equations have been adjusted after all the modifications.In order to validate the modified models’ability to capture the transition location,a Ma=7.4 Ames all-body aircraft model for natural transition and a Ma=6 flat plate installed with three dimensional roughness elements for forced transition were simulated.The results show that compared to the original model,the modified model gives much later transition location and stronger effects of the roughness elements,which agree well with the experimental results.Finally,the modified model has been applied to the simulation of hypersonic natural and forced transition of the 20%scale X-51A fore body configuration in BAM6QT.The present model can simulate not only the effects of the free stream turbulence intensity but also the promotion of the transition position by the forced transition trips.The results show the good potential of the modifiedγ-Reθtransition model in transition prediction for complex configurations in hypersonic flows.