A high-order combined interpolation/finite element technique for evolutionary coupled groundwater-surface water problem
Eric Ngondiep, Areej A. Binsultan, Ibtisam M. Aldawish
TL;DR
The paper addresses simulating evolutionary coupling between groundwater and surface water flows by a Stokes–Darcy model with interface conditions. It introduces a hybrid higher-order interpolation/finite element scheme that uses a second-order time interpolation and space discretization of degree $d$ and $d+1$, achieving unconditional stability, temporal order $2$, and spatial convergence $O(h^{d+1})$. A rigorous stability and error analysis in $L^{\infty}(0,T;L^{2})$-type norms shows the method is unconditionally stable without stabilization terms, while numerical experiments confirm the predicted convergence behavior and computational efficiency. The approach offers a robust and fast tool for solving coupled groundwater-surface water systems and is proposed for extension to 3D nonlinear multi-physics problems such as elastodynamic sine-Gordon models.
Abstract
A high-order combined interpolation/finite element technique is developed for solving the coupled groundwater-surface water system that governs flows in karst aquifers. In the proposed high-order scheme we approximate the time derivative with piecewise polynomial interpolation of second-order and use the finite element discretization of piecewise polynomials of degree $d$ and $d+1$, where $d \geq 2$ is an integer, to approximate the space derivatives. The stability together with the error estimates of the constructed technique are established in $L^{\infty}(0,T;\text{\,}L^{2})$-norm. The analysis suggests that the developed computational technique is unconditionally stable, temporal second-order accurate and convergence in space of order $d+1$. Furthermore, the new approach is faster and more efficient than a broad range of numerical methods discussed in the literature for the given initial-boundary value problem. Some examples are carried out to confirm the theoretical results.
