Drag Reduction of Truck and Trailer Combination with Different Passive Flow Control Methods

Abstract

In this study, drag force and surface pressure measurements were conducted on a 1/32 scaled truck-trailer combination model. The experimental tests were carried out between the ranges of 312×103- 844×103 Reynolds Numbers in a suction type wind tunnel. The aerodynamic drag coefficient (CD) and distribution of pressure coefficient (CP) were experimentally determined for the truck and trailer combination. The regions with a large amount of pressure coefficients were determined on the truck-trailer by using flow visualizations. The aerodynamic structure of truck-trailer combination models was improved by passive flow control methods on 4 different models. By using a newly designed spoiler on Model 1, the drag coefficient was reduced by 10.01 %. On Model 2, after adding a trailer rear extension with a spoiler, the reduction was obtained at 11.35 %. For the model 3 which is obtained by adding a side skirt to model 2, the improvement reached 18.85 %. The model 4 was composed of model 2 and a bellow between the truck and trailer. The drag force improvement was obtained at 22.80 % for model 4.