Airfoil Design Project

Project Objective

The goal of this project is to design a rear wing for our school's racing team, which operates on the same principles as an aircraft wing. Our objective is to optimize the pressure difference above and below the wing and reduce drag. The pressure difference is influenced by factors such as the curvature of the rear wing, the number of elements, the spacing between each element, and the angle of attack. Drag, on the other hand, includes form drag and skin friction, and is therefore affected by the frontal area and the total surface area of the rear wing.

Frontal Area-CL Relationship:

As the frontal area increases, the coefficient of lift (CL) decreases. We hypothesize that this is because a larger area may require a greater wing angle, shortening the reference length (or reducing the projected area at the base), which leads to a reduction in the lift coefficient.

Frontal Area-CD Relationship:

As the frontal area increases, the area exposed to wind resistance also increases, resulting in a higher drag coefficient (CD).

Settings

We set our background mesh box dimensions to 1.5m x 4m x 2m. Since the airfoil is symmetric, we applied a symmetry boundary condition to one of the walls. The inlet was set as a velocity inlet with a velocity of 15 m/s in the z-direction. The outlet was defined as a pressure outlet, with the ambient pressure set to 0 kPa.

Design and Simulation Process

In this project, we used Inventor to create 3D models and SimScale for simulation. We began by designing a single-element rear wing, using the NACA 6409 airfoil profile as a reference. Typically, an angle of attack between 0 and 15 degrees results in optimal lift. From this single-element wing, we extended the design to include two and three-element structures. Our simulations indicated that when the first element is set at an angle of 3.75 degrees and the second element at 6.63 degrees, the structure achieves the best CL/CD ratio, with |CL/CD| = 11.62.