ISSN Online: 2379-1748
7th Thermal and Fluids Engineering Conference (TFEC)
SJR: 0.152 SNIP: 0.14 CiteScore™:: 0.5
Numerical study of yaw angle and Reynolds number effects on the aerodynamic characteristics of a road vehicle
Unsteady three-dimensional computational fluid dynamics simulations are conducted to investigate the effects of wind direction on the wake characteristics and aerodynamic forces of a square-back Ahmed body. Turbulence is modeled using the Unsteady Elliptic Blending Reynolds Stress Model. A range of yaw angles (0° < β ≤ 35°) and Reynolds numbers based on body length and approach velocity (54,000 < Re ≤ 1,000,000) are studied. Results are based on analysis of the mean flow. At β = 0°, the rear wake behind the vehicle is symmetric in the horizontal plane and a small separation region is observed at the front end of the vehicle along both sides. For non-zero yaw angles, the rear wake region decreases in size and is nonsymmetric about the vehicle central plane. The separation region on the windward side of the body diminishes as β increases and disappears when the yaw angle reaches 15°. A wake region forms on the leeward side of the body, expanding as the yaw angle increases. Examination of force coefficients shows that the drag coefficient increases for β ≤ 20°, but decreases at higher angles. However, the side force coefficient increases linearly with increasing yaw angles up to β = 35°. The Reynolds number has little affect on the overall flow structure at the yaw angles in this study.