The vehicle aerodynamic and aeroacoustic performance are considered simultaneously with water management when considering the shape of the A-pillar, side mirror, and other aspects of the vehicle shape. Performance related to management of water, dirt, snow, brake dust, and other foreign particles is dependent on the small details of the vehicle surface and component design. Typically, evaluating this type of performance requires fully detailed prototypes — which are available only at the end of the design process. Fixing problems at this late stage of design is very costly in terms of engineering effort, retooling, and additional parts for the vehicle. Information about the primary performance drivers for particle management (such as exterior surface shape and engine bay layout) is needed earlier in the design process. Effects of detailed component design such as rain gutters and air intakes need to be understood before fully detailed physical prototypes are available, so the vehicle can be designed to meet performance and safety targets.
Aerodynamics simulations can provide these insights, but are also challenging. Geometry details that affect particle flows in the air and on the surface are needed. Particles flows are very sensitive to transient, turbulent flow effects, and accurate simulation of the airflow and particle trajectories is required.