改进S-A湍流模型对横向射流的CFD模拟

通过在Spalart-Allmaras(S-A)湍流模型中加入应变率张量，来改善模型对横向射流(JICF)的计算精度。模拟了速度比分别为0.5和1.5工况下的横向射流。经实验值验证，结果表明:改进后的S-A模型预测精度有所提升；并对湍流模型改进部分对横向射流的作用机制做出了分析。将改进后S-A模型的计算结果与k-ε模型，雷诺应力模型(RSM)和大涡模拟(LES)的结果进行比较，发现S-A模型在速度比为0.5时精度最高，而在速度比为1.5工况下没有明显优势；并对这一现象做出了合理分析。 

CFD simulations of jet in cross flow with modified S A turbulence model

In order to improve the accuracy of simulating jet in cross flow(JICF), Spalart Allmaras (S A) turbulence model was improved by introducing strain rate tensor into the turbulence production term because of the significant influence of shear in JICF. The JICF with velocity ratios of 05 and 15 was simulated by the modified S A turbulence model. According to the validation with experimental data, the results showed that accuracy of predicting JICF with modified S A model was promoted; mechanism of the modified parts in S-A model was also analyzed. Modified S-A model, k-ε model, Reynolds stress model(RSM) and large eddy simulation(LES) were compared in the simulations of JICF. The results showed that the modified S-A model performed best at the velocity ratio of 0.5, and had a similar accuracy to other models at the velocity ratio of 1.5; in addition, the results were analyzed reasonably.