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Validation of Pressure-Velocity Coupled Solver on Racing Car Aerodynamics

Validation of coupled incompressible pressure- velocity solver implemented in OpenFOAM is presented in this study. The pressure and velocity equation are implicitly coupled, which is accomplished by assembling the coefficients of the momentum and continuity equation into one diagonally dominant matrix. In comparison to segregated approach, coupled approach increases the convergence rate while lower under-relaxation is required. Typically, in all simulations, the limiting factor for the convergence of the system is the development of turbulent variables and boundary layers. The aerodynamic design of a racing car is important as it plays a significant role in the behaviour of a vehicle. The diffuser is situated at the rear of a racing car undertray and is of great importance for down-force generation. Exposed wheels of a racing car travelling at high speeds produce dominant effects on the drag force and also greatly influence the lift characteristics. The validation of the pressure-velocity coupled solver is carried out on two test cases. The flow around a generic 3D bluff body with a fixed diffuser angle is calculated. Force coefficients and flow characteristics are compared to experimental results. A simulation of the flow around a rotating wheel in contact with the ground is conducted, where Multiple Reference Frame (MRF) model is used for the rotation of the wheel. The results of the simulation are compared to experimental data. For both test cases, a comparison of coupled and segregated solver performance is given.

Block Coupled Solver ; Implicit Pressure-Velocity Coupling ; Car Aerodynamics ; Multiple Reference Frame ; OpenFOAM

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