A level-set method for droplet impact and penetration into a porous medium

A level-set method is presented for computation of droplet impact and penetration into a porous medium. The volume averaged conservation equations of mass and momentum are employed for the porous region including the effects of porosity and drag force caused by the porous solid matrix. They are coupled to the conservation equations in the external fluid region through the matching conditions of velocity and stress on the porous surface. Computations are conducted to investigate the effects of initial droplet radius, impact velocity, contact angles, particle size and porosity on the droplet spreading and penetration. A simple analytical formulation is developed for the initial droplet penetration depth and compared with the numerical results. The present level-set method is also applied to the computation of droplet-droplet interaction in the porous medium.