AERODYNAMICS OF SIMPLIFIED VAN-TYPE VEHICLES

摘要

We focused on the frontal shapes of vehicles which hadn't been paid attention before. So, we used 1/5 scale simplified models that had the various ratios of roof width and side height in the present study, which are 2:1, 6:5, 1:1, 5:6, 3:4, 5:8 and 1:2. We used a wind tunnel and an inhouse moving belt to attain reasonable ground simulation. We measured the aerodynamic force, the wake and the surface pressure at the wind speed of 20 m/s. The results show that the C_D value of nearly 1:1 vehicle is low at each road clearance. Because, the total pressure loss area is small and the base C_P is high. And the side C_P of oblong vehicle is lower than square vehicle. It is because the side flow of oblong vehicle is widely bent, the flow speed is increased and the pressure is low. When the road clearance is raised, the floor C_P is increased. So, the -C_L is small. Therefore, usual passenger cars which should have low fuel consumption suit the square shape that has low C_D and super cars which run at high speeds and need large down force suit the oblong shape.