Influence of Presence or Absence of Wheels on Aerodynamic Characteristics of Low-Resistance Vehicles

Abstract:

Numerical calculations are conducted for the low-resistance electric vehicle model with or without wheels， and the aerodynamic force， surface pressure， velocity field， and other calculation results of the two models are compared to evaluate the influence of wheels on the aerodynamic characteristics of the low-resistance vehicle. The results show that the presence of wheels increases the aerodynamic drag of the vehicle by 63.8%. The components which have the largest contribution are the front wheel chamber， the front of the vehicle body， the base， the underbody （negative contribution） and the rear wheel housing in descending order. The vehicle lift increases more than doubled， mainly due to the contribution of the underbody of the vehicle. The aerodynamic influence of the wheels on the vehicle is reflected in the combined effect of global blocking and local wake caused by the wheel. The wake generated by the rear wheel and the rear guide hood will enhance the strength of the tail vortex ring and reduce the length of the backflow area and the base pressure. A comparison of aerodynamic drag， lift force， pressure distribution， and flow field shows that the existence of wheels will bring significant changes to the aerodynamic characteristics of the vehicles of low wind resistance.

Key words:low wind resistance vehicle;with or without wheels;aerodynamic resistance;aerodynamic characteristics