Absorbing Boundary Conditions for Free-Surface Flows in Open Domains

MARIO ALBERTO STORTI; BATTAGLIA, LAURA; PAZ RODRIGO; D'ELÍA, JORGE

San Pablo

Congreso; 10th World Congress on Computational Mechanics (WCCM 2012), 33rd Iberian Latin American Congress on Computational Methods In Engineering (CILAMCE 2012); 2012

International Association for Computational Mechanics

Abstract. Reflection of waves at artificial boundaries degrade the quality of numerical solutions andcan prevent convergence to the infinite domain solution. Absorbing boundary conditions (ABC´s)eliminate this reflections ensuring convergence to the infinite domain solution. High order ABC´sreduce further the computational cost by allowing shorter domains for the same level of precision.The PML technique (Perfectly Matched Layer) has been applied in order to obtain very efficient highorder ABC´s, but however, they tend to be unstable. In addition, the development of the PMLabsorbing term is specific to each physical problem. In this paper we propose a technique thatdevelops an ABC for any advective-diffusive problem to any order and has the practical advantagethat can be implemented only in terms of the computation of the advective fluxes. The technique isbased on the standard expansion of the absorbing term in terms of lateral wave number and computingthe matrix coefficients for the higher order terms by polynomial fitting. Several numerical examplesare presented.