James Merkel, University of Texas at Arlington
Over the past year, use of Pointwise for computational fluid dynamics (CFD) mesh generation has helped increase productivity drastically on the Formula SAE team at the University of Texas at Arlington shown in Figure 1. In the past, we have studied the behavior of our car from an aerodynamic perspective by analyzing components such as the undertray, wings, and the full car. However, for the 2012 formula car, we plan to investigate a more aggressive aero package because of drastically relaxed design constraints. As a baseline, our current aero package produces more than 400 pounds at 67 miles per hour and features a front and rear wing as well as an underbody diffuser.
At the start of our project, we began analyzing our current wings to see if there was anything to be gained from changing the element spacing. We started iterating the placement of the flaps on our wing to find the maximum lift possible with the new set of rules. Since the study was two dimensional, we were able to use the latest anisotropic tetrahedral extrusion (T-Rex) technique in Pointwise. We found little to no increase in lift with our current wing profiles, but we were able to validate our mesh and the CFD model. It was within 10 percent of the lift and drag figures from previous wind tunnel data. Figure 2 shows our T-Rex mesh of the current wing profiles.
Now that we have developed a better understanding of our wings, we are currently working to improve the designs, starting with more aggressive, larger main planes. An example of one candidate can be seen in Figure 3. At this early stage, we only have developed data on new main planes isolated from flaps. By changing the main plane alone, we already have found a 46 percent increase in lift! We don't expect this percentage to be maintainable when we move to 3D analysis, but it still has been quite exciting to see the difference the new main planes have had. After the selection and refinement of the main plane, we plan to add the flaps, as well as a leading edge slat as necessary.
Once the optimal elements are found and placed, the study will be taken to three dimensions to optimize the endplates. This is a new study being done by our newest aero team member. She will be developing a quarter car model to analyze interactions between the tire and wing and will study ways to reduce lift on the tires. The beginnings of our model can be seen in Figure 4. Once the wings have been set, we plan to modify our full car model previously developed in Pointwise to analyze the aerodynamic interactions and study the rear wing placement.
Pointwise has been vital to updating the aerodynamic package of our Formula SAE car. We look forward to Pointwise's continued sponsorship of UTA's Formula SAE team.
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