The introduction of the Harmonized Light Vehicles Test Procedure causes a significant challenge for the automotive industry, as it increases the importance of efficient aerodynamics and demands how variations of optional extras affect the car’s fuel consumption and emissions. This may lead to a huge number of combinations of optional extras that may need to be aerodynamically analyzed and possibly optimized, being to resource-consuming to be done with wind tunnel testing merely. Reynolds Average Navier-Stoles (RANS) coupled with Large Eddy Simulations (LES) have shown potential for accurate simulation for automotive applications for reasonable computational cost. In this paper, three hybrid RANS-LES models are investigated on the DrivAer notchback and fastback car bodies and compared to wind tunnel measurements. Several yaw angles are investigated to see the model’s ability to capture small and large changes of the flow field. It is seen that the models generally are in good agreement with the measurement, but only one model is able to capture the behavior seen in the measurements consistently. This is connected to the complex flow over the rear window, which is important to capture for accurate force predictions.

中文翻译：

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评估用于精确汽车空气动力学模拟的混合 RANS-LES 方法

协调轻型车辆测试程序的引入给汽车行业带来了重大挑战，因为它增加了高效空气动力学的重要性，并要求可选附件的变化如何影响汽车的油耗和排放。这可能导致需要进行空气动力学分析和可能优化的大量可选附加组件的组合，仅通过风洞测试来完成资源消耗。雷诺平均纳维-斯托尔斯 (RANS) 与大涡模拟 (LES) 相结合，已显示出以合理的计算成本对汽车应用进行精确模拟的潜力。在本文中，三种混合 RANS-LES 模型在 DrivAer 缺口和快背车身上进行了研究，并与风洞测量进行了比较。研究了几个偏航角，以查看模型捕捉流场大小变化的能力。可以看出，这些模型通常与测量结果非常吻合，但只有一个模型能够一致地捕捉在测量结果中看到的行为。这与后窗上的复杂流动有关，这对于准确预测力来说非常重要。