A CFD Investigation into the Transient Aerodynamic Forces on Overtaking Road Vehicles Models

This paper investigates aerodynamic forces acting on the stability on both the overtaking and overtaken vehicles. The flow field around a vehicle model, which influenced by another vehicle, is analyzed by using CFD softwares. Currently, there are many researches investigating and conducting experiments related to this field. Most researches uses only 2D CFD to overcome the practical problems and uses simplified figure models in both experimental and CFD. Those researches, mostly using in-built CFD software, are limited for certain settings and experiments only. The main objectives of this project are to investigate and clarify the data and results obtained using 2D CFD by using commercial CFD softwares. There are some deficiencies occur in the previous researches that is seen to be an opportunity for further investigation. In this project, softwares which are GAMBIT, T-GRID, FLUENT, and also Microsoft Visual Studio C++ will be used to simulate the model. Simulations conducted in this project using relative vehicle velocities of Vr = 2.2, 4.5, 8.9, 13.4 m/s (7.92, 16.20, 32.04, 48.24 km/h). These relative velocities equate to velocity ratios of k = 0.083, 0.17, 0.33, 0.5, respectively. Graphs, contours and vectors obtained at the end of the simulations to enhance further understanding. The increased in Vr will decrease in time needed for the vehicles to overtake the other, also changes the vehicles static pressure in each points of the vehicles that will be discussed later in this paper. This project provides considerable interest and scope for future investigation.