Evaluation of aerodynamics and pressure distribution around a moving vehicle

Electric vehicles are gaining market dominance due to their sustainability; however, they still need to acquire superior performance with long driving range, high stability, and low operating costs. This study analyzes air pressure, velocity, and force distribution in a moving car mostly at high speeds to tap into the potential energy of moving air to charge the vehicle battery. SOLIDWORKS modeling software is used to design a 3D CAD car model. Computational Fluid Dynamics (CFD) flow simulation is further used to validate the theory of stagnation and wake pressure in the front and back of the car, respectively. A BMW 3 Series model shape is considered as base model, and it is analyzed to find the actual pressure difference trend as the car moves. The same boundary conditions are used for the entire model at a vehicle velocity range of 0 - 35 m/s. The front region of the vehicle is found to experience the highest air pressure and velocity change, translating to a significant loss of energy into other energy forms. Pressure drag is found to be a function of the pressure difference between the front and the back faces of the moving vehicle. At 5 m/s, the pressure difference was observed to be 25 Pa, whilst at 40 m/s, the pressure difference was 800 Pa, which is a considerable rise translating to an increased drag force. Simulation results were found to be coherent with the mathematical model results, thereby validating this work. This calls for further design improvement in the vehicle shape to reduce the pressure difference, hence improving the efficiency and range of the vehicle.