NEWNHAM, P. ... et al., 2006. The measurement of transient aerodynamics using an oscillating model facility. Transactions of the Society of Automotive Engineers: Journal of Passenger Cars: Mechanical Systems, 115, 2006, Paper No. 2006-01-0338.
A method for the estimation of transient aerodynamic data from dynamic wind tunnel tests has been developed and employed in the study of the unsteady response of simple automotive type bodies. The paper describes the facility and analysis techniques employed
and reports the results of a parametric study of model rear slant angle and of the influence of C-pillar strakes. The model is shown to exhibit damped, self-sustained
and self-excited behaviour. The transient results are compared with quasi-steady predictions based on conventional tunnel balance data through the calculation
of derivative magnification factors. For all slant angles tested the results show that the quasi-steady prediction is a poor estimate of the real transient behaviour. In
addition the slant angle is shown to have significant effect on the level of unsteadiness. The addition of Cpillar
strakes is shown to stabilise the flow with even small height strakes yielding responses well below that of steady-state.