Study on the strategy for improving the accuracy of aerodynamic simulation based on digital wind tunnel

With the rapid development of the new energy vehicle industry, automakers are paying more attention to aerodynamics and are increasingly demanding efficient and high-precision simulation development methods. In this paper, a digital wind tunnel model was established based on the full-scale aerodynamic acoustics wind tunnel of China Automotive Engineering Research Institute (CAERI). Comparisons were conducted wit the physical wind tunnel regarding the boundary layer thickness, pressure gradient, and turbulence intensity for the empty wind tunnel, pressure distribution on vehicle surfaces, and total pressure distribution in the wake and around the tire. The mesh adaptation technology and modified turbulence model were adopted to compute and compare three types of extended DrivAer model, namely Sedan, Fastback, and Estate, under multiple working conditions. The research shows that the mesh adaptation strategy significantly improves the efficiency and robustness of flow field calculation, reducing 21.0% of the computational time as compared to the Box mesh strategy. The k – ω turbulence model is more consistent with the wind tunnel test results in calculating the drag and lift coefficients of vehicles than the k – ε model, and can be widely used for various types of vehicles with a calculation error of less than 2%.