Abstract In this paper, the drag reduction benefits associated with 2 and 3 cars in platoon have been investigated. Following a validation of initial CFD simulations against experimental measurements, predictions of surface pressures and wake structure for alternative platoon configurations have been analysed to determine the changes of flow structure that influence the pressure field and drag force on each vehicle. Contrary to several publications it was found that in a platoon of two vehicles, the drag force of the trailing vehicle exceeded that of an isolated vehicle for close spacings. Analysis of this surprising result revealed that design features introduced to optimise the wake of an isolated vehicle can lead to a drag increase on a following vehicle. For three-vehicle platoons, the flow interaction between the leading and middle vehicles remained largely unchanged but the additional effect of the third vehicle resulted in all three vehicles exhibiting lower drag than that of an isolated vehicle. A clear implication of this work is that results from the analysis of vehicle platoons are likely to be sensitive to the geometry and wake structures of the chosen test vehicle which helps to explain why many previous studies have been seemingly contradictory.

中文翻译：

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排内车辆尾流和表面压力分析

摘要 在本文中，研究了与 2 辆和 3 辆汽车成排相关的减阻效果。在根据实验测量值对初始 CFD 模拟进行验证之后，我们分析了替代排配置的表面压力和尾流结构的预测，以确定影响每辆车上的压力场和阻力的流动结构的变化。与一些出版物相反，发现在一个由两辆车组成的排中，尾随车辆的拖曳力在近距离时超过了孤立车辆的拖曳力。对这一令人惊讶的结果的分析表明，为优化孤立车辆的尾流而引入的设计特征可能会导致后续车辆的阻力增加。对于三车排，前车和中间车之间的流动相互作用基本保持不变，但第三辆车的额外影响导致所有三辆车的阻力都低于孤立车辆的阻力。这项工作的一个明确含义是，车辆排分析的结果可能对所选测试车辆的几何形状和尾流结构很敏感，这有助于解释为什么许多以前的研究似乎相互矛盾。