This work presents a detailed wind tunnel investigation into the nature of the unsteady flow mechanisms that dictate the aerodynamic forces acting on prime-mover trailer heavy vehicles fitted with various passive flow control devices. This work builds on the current understating of the wake flow physics of heavy vehicles that until now has primarily been developed from studies utilising highly simplified geometries or time-averaged findings with realistic geometries. Unsteady base-surface and wake pressure measurements reveal how the time-averaged and unsteady flow field responds to the addition of passive aerodynamic devices that have been shown to be effective on operational heavy vehicles for improving fuel economy and reducing emissions. In comparing turbulent wake statistics and unsteady modes the time-averaged and unsteady flow response is linked directly to the measured changes in the aerodynamic drag coefficient thorough surface pressure and force measurement. The large variation in the wake structure and dynamics observed between test configurations highlights the importance of considering the detailed geometry of heavy vehicles when looking to develop advanced aerodynamic control devices that would provide benefits above and beyond those focused on in this study.

这项工作对不稳定流动机制的性质进行了详细的风洞调查，这些机制决定了作用在装有各种被动流动控制装置的原动机拖车重型车辆上的空气动力。这项工作建立在目前对重型车辆尾流物理学的低估基础上，迄今为止，重型车辆的尾流物理学主要是从利用高度简化的几何形状或具有现实几何形状的时间平均结果的研究中发展而来的。不稳定基面和尾流压力测量揭示了时间平均和不稳定流场如何响应添加被动空气动力学装置，这些装置已被证明对操作重型车辆有效，以提高燃油经济性和减少排放。在比较湍流尾流统计数据和非定常模式时，时间平均和非定常流动响应与通过表面压力和力测量的空气动力阻力系数的测量变化直接相关。在测试配置之间观察到的尾流结构和动力学的巨大变化突出了在寻求开发先进的空气动力学控制装置时考虑重型车辆详细几何形状的重要性，这些装置将提供超出本研究重点的优势。