The Simulation of Brake Dust Deposition A P Gaylard and D Lynch Jaguar Land Rover J Amodeo and R Amunugama Exa Abstract The application of brakes on a vehicle leads to the generation of a cloud of heated particles ejected from brake discs and pads, which can be entrained by the flow around the wheels and deposited on their surfaces. Under some circumstances, this may be considered inconvenient or unsightly. This paper describes the development of a brake-dust deposition simulation, using a commercially available CFD code. A range of approaches was investigated to account for the effect of wheel rotation and the propagation of brake dust particles. A comparison to simplified laboratory dynamometer experiments is presented and the most successful CFD method is applied to a full car model, providing insight into the brake-dust deposition mechanisms. Introduction As customer expectations of premium automotive product rise and the need to optimise wheel design for aerodynamics becomes more pressing, it is important to have a virtual toolset available that can assess brake dust deposition alongside brake heating and wheel system drag. This paper describes the development of a CFD brake dust deposition assessment method, using a commercially available Lattice Boltzmann (LBM) CFD method (Exa PowerFLOW). Three different approaches to accounting for wheel-rotation were investigated: applying a rotational velocity boundary condition (VBC), moving reference frame (MRF) or a sliding (rotating) mesh (RM). Additionally, two simulation techniques for modelling the propagation of the brake-dust through the flow field were examined: time-averaged Lagrangian particle tracking (ALPT) and transient Lagrangian particle tracking (TLPT). These were compared to a simplified laboratory experiment. The combination of rotating (wheel) mesh and transient Lagrangian particle tracking (RM/TLP) is shown to produce a wheel-soiling pattern that most closely resembles the experimental data. The RM/TLPT model was applied to a whole-car aerodynamic CFD model, providing an assessment method integrated into the vehicle aerodynamics / thermal management toolset, as well as insights into the brake-dust soiling mechanism.