| Popis: |
The performance of current open wheeler race cars depends heavily on the effectiveness of the aerodynamic package of which the front wing and wheels make a significant contribution. Previous investigations have focused on the aerodynamic characteristics of each of these bodies in isolation. Investigations that have considered both working in unison have conflictingly reported that the wheel presence aids or hinders the wing???s performance while the wheel???s aerodynamic performance has been neglected. In order to obtain a more thorough understanding of the interaction of a wing and wheel, experimental results were used to validate a computational model used to investigate a wing and wheel in isolation and in combination. The combined wing and wheel investigation demonstrated that three main interactions can occur, depending on the selection of wing span, angle of attack and height used, while the wheel width and track were found to have little influence. The three interacting states differ in the path that the main and secondary wing vortices take around the wheel and the subsequent variation in the combined wake structure. In general, the wing in the presence of the wheel reduced the wing???s ability to generate downforce by up to 45% due to the high pressure regions generated forward of the wheel. This was also found to alleviate the adverse pressure gradients experienced by the wing, and also reduce the drag by up to 70%. For this reason, the downforce loss phenomenon was observed to occur at a height 0.08c to 0.32c lower in comparison to the same wing in isolation, dependant on the wing span. Wheel lift and drag values were also observed to reduce in the presence of a wing by up to 65% and 38% respectively due to the influence of the wing???s flow structures have on the wake of the wheel. As a result,it was shown that the combined wing and wheel downforce and drag optima differed by up to 75% and 25% respectively to those which would be estimated if the two bodies were investigated individually and the results summed highlighting the importance of investigating these two bodies in unison. |
