Penalization Method for Eulerian Droplet Impingement Simulations Toward Icing Applications

Abstract

The numerical prediction of in-flight ice accretion generally involves geometry updates and remeshing as the ice builds up. However, the generation of body-fitted meshes around complex ice shapes is not trivial and can be repeated several times to obtain the final ice shape. The use of an immersed boundary method can simplify the mesh generation and help in the automation of the ice accretion process. This paper studies the application of an immersed boundary method to Eulerian droplet impingement simulations. A penalization method is suggested, requiring only the addition of source terms in the continuous form of the equations. The wall boundary condition must be treated with care to avoid droplets reinjection in the computational domain from a solid boundary. This is solved by the introduction of a droplet mask function in addition to the usual solid mask, providing an automatic detection of the wall boundary condition and therefore avoiding droplet reinjection. The approach is tested on canonical cylinder cases and on more realistic NACA0012 airfoil and ice horn cases. The results show that the solution from a body-fitted simulation can be reproduced using the penalization method.