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Investigation of the Effect of Tire Deformation on Open-Wheel Aerodynamics
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on April 14, 2020 by SAE International in United States
This paper introduces a finite element (FE) approach to determine tire deformation and its effect on open-wheeled racecar aerodynamics. In recent literature the tire deformation was measured optically using cameras during wind tunnel testing. Combined loads like accelerat-ing at corner exit are difficult to reproduce in wind tunnels and would require several camer-as to measure the tire deformation. In contrast, an FE approach is capable of determining the tire deformation in combined load states accurately and additionally provides the possibility to vary further parameters, for example, the coefficient of friction. The FE tire model was validated using stiffness measurements, contact patch measurements and steady-state cornering measurements on a flat belt tire test rig. The deformed shape of the FE model was used in a computational fluid dynamics (CFD) simulation. A sensitivity study was created to determine the effect of the tire deformation on aerodynamics for un-loaded, purely vertically loaded and combined vertical, lateral and longitudinal forces. In addition, the influence of these three tire deformations was investigated in a CFD study using a full vehicle model. The CFD model was validated through wind tunnel tests as well as on-road tests. Finally, a steady state cornering maneuver based on a vehicle dynamics simulation was sim-ulated using this combined approach of FE and CFD. The tire deformation included proper wheel load and slip angle for each wheel. The car model took car slip angle, car roll angle and wheel steering angle into account in order to match the real driving situation. On track measurements were used to validate the simulation results. This investigation of the real tire deformation provides much better insight into the rotating wheel aerodynamics of race cars.