Aerodynamics Evaluation of Road Vehicles in Dynamic Maneuvering 2016-01-1618

A road vehicle’s cornering motion is known to be a compound motion composed mainly of forward, sideslip and yaw motions. But little is known about the aerodynamics of cornering because little study has been conducted in this field. By clarifying and understanding a vehicle’s aerodynamic characteristics during cornering, a vehicle’s maneuvering stability during high-speed driving can be aerodynamically improved. Therefore, in this study, the aerodynamic characteristics of a vehicle’s cornering motion, i.e. the compound motion of forward, sideslip and yaw motions, were investigated. We also considered proposing an aerodynamics evaluation method for vehicles in dynamic maneuvering.

Firstly, we decomposed cornering motion into yaw and sideslip motions. Then, we assumed that the aerodynamic side force and yaw moment of a cornering motion could be expressed by superposing linear expressions of yaw motion parameters and those of sideslip motion parameters, respectively. Next, we conducted CFD analyses of a vehicle in dynamic meandering motions. Then, we verified the linear aerodynamic force model with the CFD analysis results. The results revealed that the aerodynamic side force and yaw moment in dynamic meandering motion could be mostly expressed with the linear aerodynamic force model. We also clarified the aerodynamic characteristics of the vehicle in dynamic meandering motion and its generation mechanism by analyzing the surface static pressure distribution on the vehicle in dynamic meandering motion by applying the concept of the linear aerodynamic force model.