Rain management and soiling affect the safety, handling and aesthetics of passenger vehicles. Dirt obscures the lights; snow and ice deposition on the rear of the vehicle alter the aerodynamics; dirt detracts from the general appearance; and when occurring on areas such as door handles can affect passenger comfort. The trends towards virtual product development (VPD) and better physics modelling are together making simulation of vehicle soiling more viable and increasingly desirable.

Well-established and efficient CFD methodologies are exploited at ICON. These include Lagrangian-Eulerian two-phase and coupled particle tracking of discrete particles in an airflow continuum, liquid-film formation due to impingement of droplets on the surface, resulting liquid-film transportation, and droplet stripping (re-entrainment) back into the continuum airflow due to edge effects of film instability. A liquid film transportation model accounts for many physical effects including film-continuum shear, pressure-gradient, gravitational and inertial effects.

Validations of these methodologies are performed by ICON together with their application to production vehicles.