The Experimental Investigation of the Effects of Spoiler Design on Aerodynamic Drag Coefficient on Truck Trailer Combinations

Abstract

In this study, surface pressure and drag force measurement was measured at 6 different free flow velocities on a heavy vehicle model, consisting of truck and trailer, placed in the wind tunnel. The aerodynamic drag coefficient were determinated for three different models which are unspoiler model, the standard spoiler and new design spoilers model. As a result of wind tunnel tests, the effects of spoiler design on the aerodynamic drag coefficient was defined. The experimental studies were performed on 156000- 844000 Reynolds number. In experimental studies, kinematic similarity was provided and blocking effects were neglected. In the dynamic similarity condition, the independence of Reynolds number was used. The pressure coefficient distributions on the vehicle were determined with the experiments of pressure measurement. The pressure coefficient was found to be high at the top of the trailer which is higher than truck and on the front bumper. % 11.37 the aerodynamic improvement was obtained by new spoiler design according to the model 2 with standard spoiler.