An experimental study of unsteady vehicle aerodynamics
An experimental study of unsteady vehicle aerodynamics
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非定常车辆空气动力学实验研究
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
A. Imam
中科院分区：
文献类型：
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作者：
M. Passmore;S. Richardson;A. Imam
摘要 车辆对风扰动的瞬态响应对于汽车驾驶员来说非常重要，因为低水平输入可能导致车辆精细度较差，而极端影响可能导致路径偏差。本文研究了使用振荡翼型阵风发生器来模拟在简化的正弦侧阵风相互作用期间汽车型钝体上产生的瞬态空气动力效应。根据模型长度，简化的钝体受到一系列正弦侧风激励，对应于 0.09 至 0.71 之间的降低频率。处理表面压力的非稳态测量以确定侧向力和偏航力矩，并通过将瞬态响应与准稳态预测进行比较来计算气动放大率 (χa)。瞬态横摆力矩响应超过准稳态响应高达 30%。除测试的最低频率外，瞬态侧向力通常明显小于准稳态值。响应的变化归因于前柱涡流和后柱涡流强度的变化以及相对于准稳态响应的相位变化。
Abstract The transient response of a vehicle to a wind disturbance is of importance to car drivers since low level inputs can result in poor vehicle refinement, and extreme effects can result in path deviation. This paper investigates the use of an oscillating aerofoil gust generator to simulate the transient aerodynamic effects produced on a car-type bluff body during a simplified sinusoidal side gust interaction. A simplified bluff body was exposed to a range of sinusoidal cross-wind excitations corresponding to a reduced frequency of between 0.09 and 0.71 based on the model length. Unsteady measurements of surface pressure are processed to determine the side force and yaw moment and the aerodynamic magnification (χa) is calculated by comparing the transient response with a quasi-steady prediction. The transient yaw moment response is shown to exceed the quasi-steady by as much as 30 per cent. The transient side force is generally significantly less than the quasi-steady value except at the lowest frequency tested. The change in response is attributed to changes in the strength of the front and rear pillar vortices and to changes in phase relative to the quasi-steady response.