UNSTEADYWAKE OF A PASSENGER CAR MOOEL

How around an automobile is usually considered as steady phenomenon. Aerodynamic coefficients, the most imponant of which is the drag coefficient, are regarded as constants because of the steady flow around the vehicle body. Them is a thought however, the flow separations and the vortical motions around the body me unsteady and the constant drag coefficient can be obtained as a time averaged value of unsteady forces. The present study has been carried out horn this view point The unsteady wake structure up to 300 Hz of a scale vehicle model was measured using 252 total pressure probes. The measuring system is based on ESP (Electronically Scanned Pressure) sensors, which is very popular in the wind engineering field. The results show the wake of the vehicle model has unsteady structure.