A New Aerodynamic Approach to Advanced Automobile Basic Shapes
A New Aerodynamic Approach to Advanced Automobile Basic Shapes
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先进汽车基本形状的新空气动力学方法
DOI：
10.4271/2000-01-0491
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
A. Morelli
中科院分区：
文献类型：
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作者：
A. Morelli
空气动力学基本形状通常是指在离地面很小的距离上移动的非轮式物体，有效且适合于汽车应用。此外，形状的设计要符合空气动力学以外的要求，以尽可能小的总尺寸容纳乘员、行李和机械部件。然而，即使基本的车身阻力系数可以低至0.05，车轮的增加可能会增加车身阻力，由两到三倍。新方法从定义空气动力学标准开始，如总升力接近于零，俯仰力矩符号和值与道路保持和稳定性一致，对侧风的敏感性降低，横截面的逐渐变化等。然后，考虑到车轮的存在，以减少其与车身的空气动力学干扰，并管理尾流机制，以回收气流的动能，而无需在车身上安装实心扩散器：事实上，这将增加车身长度，而不会对可用空间产生太大影响。理论和实验工作导致一个新的形状，特别是在后部短，能够改善乘客在后座的住宿和目前的一个主要缺点，实际汽车的能见度与空气动力学阻力的好处一起显示。最后讨论了该方法的应用所带来的其他优点。
Aerodynamic basic shapes are generally intended as non wheeled bodies moving at a small distance from the ground, effective and suitable for automobile applications.The shape is furthermore designed to comply with requirements other than aerodynamic accomodating occupants, luggage and mechanical parts within as small as possible overall dimensions. However, even though the basic body drag coefficient can be as low as 0.05, the addition of wheels may increase the body drag, by two to three times. The new approach starts from the definition of aerodynamic criteria such as total lift close to zero, the pitching moment sign and value consistent with road holding and stability, a reduced sensitivity to side wind, gradual variation of the cross sections, etc.. Then, the presence of the wheels is taken into account in order to reduce their aerodynamic interference with the body, and to manage the wake mechanisms in order to recover the kinetic energy of the flow without fitting the body with a solid diffuser: in fact, this would increase the car length without contributing much to the usable space. Theoretical and experimental work leading to a new shape particularly short in the rear part and able to improve both the accomodation of passengers in the rear seats and the visibility outside at present a major drawback of actual cars are shown together with aerodynamic drag benefits. Other advantages resulting from the application of the method are finally discussed.