Abstract
Wind induced sideways response on passenger cars is one of the concerns on vehicle stability which affects driving comfort and sometimes safety, especially under strong crosswinds.
The dynamic response of cars in turbulent winds is investigated in four wind-tunnel experiments: a 1 :12 sharp- edged car model; a 1 :10 Audi A4 model; and a racing and passenger full-scale car. The resultant side force spectra for various turbulence levels were measured which showed a phenomenon not previously observed in cars: the side force spectral bandwidth becomes nar- rower with increase in turbulence. The vortex-shedding Strouhal number of the cars was found to be 0.27.
As this can be close to the natural frequency of cars, it is suggested that suspensions be tuned accordingly to improve driving comfort and avoid vehicle instability. The findings could also be helpful in creating an active suspension of passenger cars. In addition, the study emphasises that turbulence should be modelled by dynamic testing in wind tunnels.