Numerical Assessment of the Aerodynamic Properties of a Solar Vehicle

Abstract

Due to wide emphasis on climate change today, alternative fuel research is necessary. Consequently, the South African Solar Challenge has created a competitive platform for research into alternative energies, particularly solar. The University of Johannesburg (UJ) competed in the competition using their uniquely designed and built solar vehicle, Ilanga I. However, due to the constraints of the energy available, the aerodynamics of the vehicle has to be exceptionally good. Subsequently, a large proportion of the total power of the vehicle is used to overcome the aerodynamic resistance posed by the vehicle. Furthermore, much of the remaining power of the vehicle is used to overcome rolling resistance. Consequently, solar vehicles have to be as lightweight as possible in order to effectively reduce the rolling resistance. However, reducing weight of the vehicle results in the vehicle’s stability being greatly affected by side-wind effects. In order to improve on the vehicle, it is very important to test for and obtain its aerodynamic characteristics. This research article aims at obtaining the average drag coefficient felt during the majority of the race as well as the lift coefficients for side-wind cases, in order to investigate vehicle safety. Thus, through the use of Computational Fluid Dynamics (CFD), it was possible to obtain an assessment of the vehicle’s performance. Simulations were performed using the Reynold’s Averaged Navier Stokes (RANS) method with use of the k-ω SST turbulence model. This method of simulation showed reasonable predictions of the results as compared to literature.