Abstract. In this paper, we consider the boundary stabilization problem associated to the 1 − d wave equation with both variable density and diffusion coefficients and to its finite difference semi-discretizations. It is well-known that, for the finite difference semi-discretization of the constant coefficients wave equation on uniform meshes [24] or on some non-uniform meshes [20], the discrete decay rate fails to be uniform with respect to the mesh-size parameter. We prove that, under suitable regularity assumptions on the coefficients and after adding an appropriate artificial viscosity to the numerical scheme, the decay rate is uniform as the mesh-size tends to zero. This extends previous results in [24] on the constant coefficient wave equation. The methodology of proof consists in applying the classical multiplier technique at the discrete level, with a multiplier adapted to the variable coefficients.
PreliminariesLet us consider the following initial boundary value problem associated to the 1 − d wave equation with variable coefficients and with a damping mechanism acting on the right endpoint of the space interval:Here we have taken the dissipative boundary condition σ(1)v x (1, t) + v t (1, t) = 0, but similar results can be proved for more general feedback terms as, for instance,with k > 0 and k = 1. In fact, problem (1.1) with the second dissipative condition can be reduced to (1.1) by scaling the time variable.The energy corresponding to the solution of (1.1),obeys the following dissipation law:When the variable coefficients ρ and σ belong to the BV (0, 1) class of functions with bounded variation, the following stabilization property holds, ensuring the exponential decay of the energy E ρ,σ (v(·, t), v t (·, t))The main idea of this work originated when the first author has visited BCAM in December 2012.