Characterization of kinetic loads from aerodynamic induced effects

Abstract

Motorsport racing engineers are constantly on the lookout for new methods which can aid or enhance downforce generation. Recently, the Fédération Internationale de l'Automobile (FIA) has lifted the ban on downforce generation through ground-effect by amending the 2022 season Formula 1 (F1) technical regulations. However, due to unforeseen fluid dynamics, during the season opening races, most F1 cars were suffering from aerodynamic induced bouncing, termed as ‘porpoising’. The aerodynamic phenomenon arose from the ride height sensitivity of the ground-effect. Consequently, a two-way interaction between the aerodynamic forces produced by the vehicles and their suspension dynamics was taking place. Thus, in this project, a computational method for simulating this two-way interaction was developed so as to investigate said interaction’s effects on the dynamic motion and kinetic (dynamic) loading of the cars. Computational Fluid Dynamics (CFD) was employed to simulate the aerodynamics of a ground-effect car. Moreover, a two-dimensional (2D) CFD model making use of a compressible solver was developed and validated through comparison with published data for an experimental investigation on the aerodynamics of a wing in ground (WIG) effect. Using the same published data, two turbulence models were compared, and the Spalart-Allmaras model was selected as it resulted in more accurate solutions. The CFD model was then used to generate aero maps for a simplified ground-effect car. It was concluded that the simplified vehicle only operated in what is known as the force reduction regime. A two-way interaction numerical model was then developed, and the aero map data was imported into said model. By simulating the vehicle at a constant speed and during a hard braking manoeuvre (a deceleration rate of 2.4𝑔), the vehicle’s dynamic behaviour was examined. A conclusion was reached that a ground-effect car which operates only within the force reduction regime is stable and does not experience porpoising. Instead, the entire system reaches dynamic equilibrium and the car travels at a constant ride height. Recommendations on how to develop the two-way interaction model and the CFD model further were given, along with other possible studies which can make use of the developed computational method.