This video shows the CFD results of water spreading of front and side windows of a car driving (150 kmh) in the rain. A fast soiling of side windows of a driving car during raining conditions results often in obscured visibility on the exterior mirrors and this is a substantial risk for safe driving conditions. Not every new vehicle design provides best conditions for the car water management at the transition between front screen and roof. Some a-pillar concepts and mirror geometries are also not suitable for water transportation away from the exterior mirror area at the side windows.
Comprehensive CFD simulation tools allow a detailed analysis of the air flow around the car and of air vortex caused by the exterior mirrors. Water management can be simulated by different multiphase flow models like Fluid-Film or Volume of Fluid. In the example shown the coupled simulation of the front screen wiper movement allows a realistic representation of the water spreading during rainy driving situations.