Spatially dispersionless, unconditionally stable FC-AD solvers for variable-coefficient PDEs
This work provides efficient, stable solvers for variable-coefficient PDEs, which are crucial for simulating heterogeneous media in engineering and physics.
The authors present fast, unconditionally stable high-order solvers for variable-coefficient PDEs in smooth domains, achieving FFT speeds and no spatial dispersion. The methods demonstrate high accuracy on diffusion and wave propagation problems in heterogeneous media.
We present fast, spatially dispersionless and unconditionally stable high-order solvers for Partial Differential Equations (PDEs) with variable coefficients in general smooth domains. Our solvers, which are based on (i) A certain "Fourier continuation" (FC) method for the resolution of the Gibbs phenomenon, together with (ii) A new, preconditioned, FC-based solver for two-point boundary value problems (BVP) for variable-coefficient Ordinary Differential Equations, and (iii) An Alternating Direction strategy, generalize significantly a class of FC-based solvers introduced recently for constant-coefficient PDEs. The present algorithms, which are applicable, with high-order accuracy, to variable-coefficient elliptic, parabolic and hyperbolic PDEs in general domains with smooth boundaries, are unconditionally stable, do not suffer from spatial numerical dispersion, and they run at FFT speeds. The accuracy, efficiency and overall capabilities of our methods are demonstrated by means of applications to challenging problems of diffusion and wave propagation in heterogeneous media.