Numerical Investigation of the Effect of Different Airfoil Profile of a Spoiler in a Car

Abstract

With the speed changes, aerodynamic vehicles experience issues such as instability, drag and lift increasement, and so on. A great amount of lift force is created at the back end of the vehicle when a person drives a vehicle at a high speed, which can be reduced by attaching a spoiler at the rear side of the car. This paper shows the influence of the rear spoiler in an aerodynamic vehicle and the changes that occur when a rear spoiler is mounted. The right height of the rear spoiler from the rear trunk at a constant high speed and constant angle of attack is being investigated here. To obtain those results, 2 symmetric and 1 cambered type NACA Airfoil is being analyzed as a rear spoiler with the help of CFD. CFD (Computational Fluid Dynamics) is a set of numerical algorithms used to estimate the solution of fluid dynamics and heat transport issues." A BMW 3 series car model is used here which is being modeled in solidworks19 and then imported in ANSYS Fluent (2020R2). The k-omega SST turbulence model was chosen. A new rear spoiler is utilized as a consequence of an examination of the simulation results, which demonstrates a slight reduction of the vehicle aerodynamics lift force with the optimization of lift and drag force. Among the three types of naca profile, it can be seen that NACA 0012 provides more downforce (38%) than the other two types NACA 0012 (37.8%) and NACA 2412 (32.5%) when they are used as a rear spoiler in a car at Reynolds number 2.68. Even though spoilers are often attached to a vehicle to minimize lift force, they increase drag force in this case, as seen in this research. From a safety standpoint, reducing aerodynamic lift is more critical than reducing aerodynamic drag. The best height of the spoiler from the rear tank is 0.4 times than distance between the rear trunk and the upper surface of the car body in which more amount of downforce is generated.