A Penalization Method for 2D Ice Accretion Simulations 2019-01-1939

Numerical tools for 3D in-flight icing simulations are not straightforward to automate when seeking robustness and quality of the results. Difficulties arise from the geometry and mesh updates which need to be treated with care to avoid folding of the geometry, negative volumes or poor mesh quality. This paper aims at solving the mesh update issue by avoiding the re-meshing of the iced geometry. An immersed boundary method (here, Penalization) is applied to a 2D ice accretion suite for multi-step icing simulations. The suggested approach starts from a standard body-fitted mesh, thus keeping the same solution for the first icing layer. Then, instead of updating the mesh, a Penalization method is applied including: the detection of the immersed boundary, the Penalization of the volume solvers to impose the boundary condition and the interpolation of the surface data from the field solution. Although the current work is intended for 3D simulations, the content of this paper is limited to 2D applications as it is sufficient to show the feasibility of the method. Tests are preformed on multi-step rime and glaze ice cases where it is observed that the Penalization method is able to produce sensible ice shapes compared to a body-fitted approach. However, accurate results are only achieved if the mesh is a priori refined in the zone where ice accretion is expected. The paper will further discuss the computation time, mesh refinement requirements, accuracy, limitations and recommendations for improvement of the Penalization method applied to icing.