汽车车型对三车队列行驶气动阻力的影响

Effects of Vehicle Types on Aerodynamics of Three Vehicle Platooning

摘要:

采用数值模拟方法研究3种MIRA汽车车型（方背车、快背车和阶背车）对三车队列在一倍车长间距下气动阻力的影响。通过对27种编队工况下的整体队列和单车各部位气动阻力以及车间流场进行详细分析，结果表明：头车受到中车阻塞造成其背部压力回升，3种车型作为头车，自身均可实现减阻；中车由于头尾车和自身车型的共同作用，会受到背部压力回升，前部正压以及前缘圆弧负压减弱的综合影响，3种车型的中车阻力有减有增；尾车受中车和自身车型共同作用，压力变化同中车类似，阻力也有减有增。前车的低速尾流区会对后车起到庇护作用，但也会造成后车前缘圆弧部位吸力减小，不利于队列减阻，甚至造成增阻。三车队列最佳编队是快背头车—方背中车—方背尾车，减阻量可达0.12（120 counts）。

Abstract:

The effects of three MIRA bodies， i.e.， squareback， fastback， and notchback， on the aerodynamic resistance of three vehicles in platooning are numerically explored at one-vehicle spacing. A detailed analysis of the resistance of the whole vehicles and individual parts as well as inter-vehicle flow under 27 different platooning configurations shows that the back pressure of the head vehicle rises due to the blockage of the middle vehicle. All three types of head vehicle can achieve resistance reduction for themselves. The resistance of the middle vehicle will be affected by the back pressure rebound， weakening of the front positive pressure and front edge arc negative pressure due to the combined effect of the head， middle， and trailing vehicles. Thus， some cases of the middle vehicle in platooning have a low resistance and some have a high resistance. The pressure and resistance changes of the trailing vehicle is similar to those of the middle vehicle in view of the combined effect of the middle and the trailing vehicle types. The low-speed wake region of the preceding vehicle is beneficial to the resistance reduction of the following vehicle， but it will also reduce the suction of the arc at the front edge of the following vehicle， which has a negative effect on the platooning drag reduction， and even increases the whole resistance. The best configuration of the three-vehicle platooning is the fastback head vehicle， squareback middle vehicle， and the notchback trailing vehicle with a resistance reduction of up to 0.12（120 counts）.