A numerical wind tunnel framework: High-fidelity modeling for automotive aerodynamic development

With the continuous emergence of new industries in the new energy sector, the rapid development of new energy vehicles has greatly facilitated daily life. However, the increase in the driving speed of new energy vehicles leads to higher aerodynamic drag during operation, significantly reducing their range. Research on drag reduction for new energy vehicles has become particularly important. Currently, full-scale wind tunnel testing and Computational Fluid Dynamics (CFD) numerical simulations, each with their own advantages and disadvantages, are commonly used. To combine their strengths while avoiding their limitations, this study establishes a numerical wind tunnel model, using numerical wind tunnel simulations to reduce the effort required for wind tunnel testing. An existing full-scale wind tunnel is improved by adding a three-stage boundary layer removal device, among other modifications, enabling the wind tunnel model to achieve advanced performance metrics. Based on this, a numerical simulation of an electric vehicle model is conducted, comparing its aerodynamic drag coefficient and corresponding velocity field contours between the numerical wind tunnel and an open-road computational domain. The simulation strategy is adjusted to derive suitable steady-state SST k-ω and transient DES modeling approaches for this electric vehicle model.