Mechanical, Automotive & Materials Engineering, University of Windsor, Windsor, ON, N9B3P4, Canada; Mathematics & Statistics, University of Windsor, Windsor, ON, N9B3P4, Canada
Ron M. Barron
Department of Mechanical, Automotive & Materials Engineering, University of Windsor, Canada; Department of Mathematics and statistics, University of Windsor, Canada
University of Saskatchewan, Collage of Engineering, 57 Campus Drive, Saskatoon, S7N 5A9; Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, Ontario, N9B3P4, Canada; Department of Civil and Environmental Engineering, University of Windsor, Windsor, Ontario, N9B 3P4, Canada
Mathematics & Statistics, University of Windsor, Windsor, ON, N9B3P4, Canada
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.