EFFECT OF STEADY AIRFLOW FIELD ON DRAG AND DOWNFORCE

The purpose of this study is to examine the effect of the steady airflow field of a rear spoiler on the coefficients of drag (C-D) and downforce (C-DF). The type of spoiler is suggested as a two-jointed arm model that mimics the flapping flight mechanism of the Canada goose, Computational fluid dynamics (CFD) technique was used for the steady airflow analysis of a vehicle implemented with various spoiler topologies. We evaluated C-D and C-DF due to the three types of airfoils and the five phases of each airfoil. We obtained the following conclusions from the results: (1) We found that the best cases for C-D and C-DF were the case of Phase 5 and symmetry airfoil, and the case of Phase 1 and reverse airfoil, respectively. (2) It is clear that C-D becomes the largest at Phase 1 of the reverse airfoil, since the eddy magnitude at the rear of the vehicle is the largest, and C-DF also becomes the largest during that phase, since the pressure distribution on the upper surface of the spoiler is very large. (3) As Phase 1 moves to Phase 5 in the same type of airfoil, it is advantageous for C-D and disadvantageous for C-DF, respectively.