The Effect of Groundplane Boundary Layer Control on Automotive Testing in a wind Tunnel

Two different techniques, ground plane suction and blowing, were used in order to decrease the displacement thickness of the floor boundary layer in wind tunnels upstream of full-scale vehicles.

A detailed description of both systems is given and comparison tests in three different wind tunnels were carried out.

The vehicles tested were full-size passenger cars and simplified-model cars of notch back, fast back and wagon back type, as well as sport cars and a racing car with different trim heights simulating different ground clearances.