The aerodynamic design and development ol' the University of New South Wales' ultra-low-drag solar-electric Sunswitl IV car is described, detailing the student-led design process n•om initial concept sketches to the completed vehicle. The body shape was established and relined over a period of six months in 2008-2009, almost entirely using computational lluid dynamics. The guiding philosophy was that predictable handling and drag minimisation in challenging, changing wind conditions of the type commonly seen during the World Solar Challenge across Australia was prelerable to high performance only on 'perfect' days. The car won its class in the 2009 and 2011 World Solar Challenges, and holds the Guinness World Record for last est solar-powered vehicle.

This article highlights the 'synergistic' use of experimental fluid dynamics (EFD) and computational fluid dynamics (CFD), where the two sets of simulations are performed concur rently and by the same researcher. In particular, examples from the area of ground effect aero dynamics are discussed, where the major facility used was also designed through a combination of CFD and EFD. Three examples are than outlined, to demonstrate the insight that can be obtained from the integration of CFD and EFD studies. The case studies are the study of dimple flow (to enhance aerodynamic performance), the analysis of a Formula-style front wing and wheel, and the study of compressible flow ground effect aerodynamics. In many instances, CFD has been used to not only provide complementary information to an experimental study, but to design the experiments. Laser-based, non-intrusive experimental techniques were used to provide an excellent complement to CFD. The large datasets found from both experimental and numerical simulations have required a new methodology to correlate the information; a new post-processing method has been developed, making use of the kriging and co-kriging estima tors, to develop correlations between the often disparate data types.

Flow separation is a source of aerodynamic inefficiency, by using vortex generators flow separation can be controlled. This is of particular benefit to flows around bodies which are susceptible to separated flows, such as bodies in ground effect. Previous studies on the ability of dimples to produce vortices for flow mixing concerned heat transfer applications. Experimental measurements using Laser Doppler Anemometry (LDA) were taken in the wake of the Tyrrell026 aerofoil (Rec= 0·5 × 105) with a dimple array machined in the surface. Results for a dimple array of three rows placed forward ofx/c= 0·23 with 1·5Ddimple to dimple spacing, showed significant flow recovery in the wake. The velocity deficit ofu/Uo,min= −0·1 recovered tou/Uo,min = 0·3 with the dimple array and the size of the wake reduced by 50%; at α = 10°,h/c= 0·313. The positive effect of the dimple array on the wing reduced as the wing was brought closer to the ground.

Three-dimensional laser Doppler anemometry is a powerful, non-intrusive measurement technique. The high data rate point measurement allows direct quantification of turbulence quantities. However, for this type of study, a very high level of laser beam alignment is required; without good alignment only mean flow measurements are possible. We report here on an alignment procedure that is simple and cost-effective, yet results in much higher data rates than traditional, pinhole-based methods.

Dimples used as sub-boundary layer vortex generators have been shown to reduce wake size at large angles of incidence. The effect these dimples have on wingtip vortices with an endplate is measured via laser Doppler anemometry (LDA) on an inverted Tyrrell026 airfoil (ReC = 0.5 × 105 and chord = 0.075 m) in ground effect in order to determine the flow characteristics for this configuration and to see if previous measurements were performed in a thinner part of the wake due to any potential wake waviness. The strength of the wingtip vortex for the dimpled wing is 10% higher than the “clean” wing immediately downstream. The clean wing has large region of high turbulence throughout the wake, and the dimples reduce this by 50%. The net result is that dimples drastically improve the flow in the wake of the wing and endplate.