Numerical simulation of wetting on vehicle's windshields
Examensarbete för masterexamen
In this project, the spreading dynamics of a single droplet over surfaces with different wettability conditions are studied by means of a series of numerical simulations aiming to model the motion of a rain droplet over vehicles’ windshields. To do so, a Cahn-Hilliard formulation of the Phase Field (PF) is employed. The wettability of the surface is modelled by imposing a contact angle. During the spreading process, the three-phase contact line moves over the surface while the prescribed contact angle is fulfilled. to successfully remove the well-known contact line singularity problem, a dynamic contact angle together with a slip velocity boundary conditions are imposed at the surface. Given the variety of parameters governing the dynamics of the problem, including properties of each phase (viscosity, density, etc.) the angle of the windshields, surface wettability, relative wind velocity, thermo-physical properties (such as ambient temperature ,cabin temperature) and considering computational costs, the focus of this study is on the effects of windshields’ angle, relative wind velocity and surface wettability. To further investigate the problem, several additional simulations have been performed for selected cases to scrutinize the effects of fluid properties.
phase field method (PFM) , contact line dynamic , interface , diffuse interface (DI) methods