On the Near Wake of Rotating, 40%-Scale Champ Car Wheels

This paper presents the results of an investigation of the near wake of isolated, cambered and un-cambered, 40%-scale, non-deformable Champ Car wheels rotating in ground contact. Three-dimensional velocity measurements were made in their near wakes using Laser Doppler Anemometry. Inspection of the derived velocity contours, vectors and vorticity contours, suggested that several of the theoretical vortical structures are suppressed by ‘real’ wheel geometry and the presence of a support sting. Drag force measurements were made, revealing the cambered wheel to have 12% higher drag coefficient than the un-cambered equivalent.