A localized mesh-free radial basis function-finite difference framework with shape parameter adaptive damping for stable time-domain wave simulation in extreme-contrast media
摘要
Numerical simulation of time-domain wave propagation in heterogeneous materials with extreme eight-to-nine-order magnitude contrasts in conductivity and permeability poses significant stability challenges for grid-based finite difference time-domain methods. We present a localized mesh-free radial basis function-finite difference (RBF-FD) framework augmented with shape parameter adaptive damping tuning (DAT) to deliver robust and accurate solutions. DAT dynamically optimizes the mesh-free shape parameter c as our method’s local damping actuator using a neural network (NN) trained on datasets generated by an improved random walk algorithm. The NN predicts c based on local wave frequency, physical damping, and node density