Closure coefficient modification of SA turbulence model combined with machine learning
This paper presents a combined approach integrating the modified Morris clas-sification and screening method with extreme gradient boosting(XGBoost),driven by computational fluid dynamics(CFD)data.The methodology is applied to modify the closure coefficient of the Spalart-Allmaras(SA)turbulence model.The utilization of the classification and screening method effectively narrows the research scope of the closure coefficient.Using the XGBoost method,a highly accurate fitting model can be obtained even with a small-scale data set,leading to effective improvements in the efficiency of coef-ficient modification.Employing this method,numerical experiments are conducted for the flow over the three-dimensional(3D)DLR-F6-WB configuration.The experimental results demonstrate the method's capability to rectify coefficients on complex 3D models based on small sample data.Consequently,the accuracy of the modified lift-drag coefficients has been significantly improved.