γ-Re_(θt)-CF转捩模型在Spalart-Allmaras湍流模型中的推广及验证

Genevalization and validation of γ-Re_(θt)-CF transition modeling in combination with Spalart-Allmaras turbulence model

横流(CF)不稳定性是三维流动中诱发转捩的一项非常重要的因素,考虑到γ-Reθt-CF转捩模型对流向Tollmien-Schlichting波和横流波不稳定性引起转捩的判定均是完全基于当地变量,且Spalart-Allmaras(SA)湍流模型计算效率高,因而将γ-Reθt-CF转捩模型与SA湍流模型相结合,并将其引入开源Standford University Unstructured(SU2)计算流体力学分析平台。为了考察和验证模型的预测精度,分别使用原始γ-Reθt模型和γ-Reθt-CF-SA模型,对NLF(2)-0415后掠翼型和标准6∶1椭球模型进行了转捩预测数值模拟。算例结果表明,γ-Reθt-CF-SA模型的计算结果与试验数据吻合程度远远优于原始γ-Reθt模型,γ-Reθt-CF-SA模型能正确地预测出三维流动中的横流不稳定性引起转捩的现象。

One of the major 3Dtransition mechanisms is transition due to crossflow（CF）instability.Theγ-Re_（θt）-CF transition model is a local correlation-based approach for prediction of transition caused either by Tollmien-Schlichting steamwise instability or crossflow instability.In order to improve the efficiency,γ-Reθt-CF-SA model is coupled with the one-equation Spalart-Allmaras（SA）turbulence model,and is then implemented in open-source Standford University Unstructured（SU2）,aplatform for computational fluid dynamics analyses.In order to validate and assess prediction accuracy of new model,a series of transition flows are simulated including NLF（2）-0415 swept airfoil and 6：1prolate spheroid standard model.Computation results usingγ-Reθt-CF-SA model are in good agreement with available experimental data,far superior to those using originalγ-Reθtmodel.Model proposed can effectively predict location of crossflow instability transition.