Aerodynamic study and design of an FSAE-type vehicle's front wing

Abstract

The field of motorsport requires extensive study for the design of a prototype racing car, as the parameters that affect the final result are numerous and complex. In this thesis, a detailed aerodynamic and static study is carried out in order to optimize the front wing of the Poseidon Racing Team's (UniWA) racing vehicle, aiming for the most efficient design solution. All the main aerodynamic variables governing the field of fluid mechanics, the objectives and main characteristics related to motorsport (more specifically the Formula Student institution), as well as the necessary information concerning the methodology, which mainly includes design solutions, computational fluid dynamics (CFD) and finite element analysis (FEA), are described in the first chapter of the thesis. The methodology applied was based on the objectives set from the beginning of the study, which in brief are to achieve the maximum negative lift that the front airfoil can produce, and to keep drag forces at low values. As part of the design, the dimensions and geometries were based on the regulations set by the Formula Student competition and literature references regarding the most dominant standard airfoil geometries used in motorsport. In addition, the available computational and time resources of the team were taken into account, as the facilities and time for the study and design of the airfoil are limited. The parameters and settings of the CFD analyses in which the computational model, the mesh properties, and the area in which the geometries (fluid domain) will be placed were determined by specific processes described in the methodology chapter. The CFD model that has been used is RANS. The optimal solution, according to the available resources, was found through 5 sets of analyses, which determined the standard airfoil that was used, the height at which the front airfoil was placed, the angles of attack of the two wings that were used, as well as the horizontal and vertical distance between the two. Once the CFD analyses were completed, the final design, which includes the wing mounts and external wing supports, which also help in optimizing the flow as described in Chapter 3, was statically analyzed by means of Finite Element Analysis, in order to prove that the final geometry complies with the regulations concerning the airfoil structure. Using the space available from the regulations, the length, width, and height of the airfoil are 545, 1305 and 180 mm respectively. The standard airfoil used is the Selig 1223, at an angle of attack of 3 degrees for the primary flap which was placed 50 mm above the ground, and 35 degrees for the secondary (flap), as the horizontal distance between them is 10 mm, and the vertical distance is 30 mm respectively. For the static analysis, a vertical equally distributed force of 5000 N, was applied on the geometry in order to test its maximum displacement. The material of the assembly was decided to be carbon fiber reinforced with epoxy (due to its high strength and its low weight). The maximum displacement of the geometry resulted to be 2.87 mm, which is within the acceptable range of 10 mm that is set by the competition. For design and safety reasons, the maximum acceptable displacement of the geometry was reduced to 6.5 mm (1.5 safety factor was applied).