Two-Dimensional Locally Adaptive Non-Hydrostatic Extension of Shallow Water Equations

Kemal Firdaus; Jörn Behrens

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arXiv · 2606.27562

Two-Dimensional Locally Adaptive Non-Hydrostatic Extension of Shallow Water Equations

Kemal Firdaus·Jörn Behrens

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Abstract

We introduce a two-dimensional non-hydrostatic model for shallow water wave dispersion. The model is based on a locally adapted application of a non-hydrostatic correction to the hydrostatic shallow water equations (SWE) in a predictor-corrector scheme. Applying the non-hydrostatic correction uniformly to the entire domain demands a high computational cost, since an elliptic system of equations needs to be solved for the correction terms. We demonstrate that by determining the area where the non-hydrostatic effects are significant, and applying the correction only locally, the computational effort can be reduced by approximately 40\% without sacrificing accuracy in tsunami-like scenarios. As indicators for the non-hydrostatic effect, we use the ratio between total water depth and surface elevation, as well as horizontal velocity norms. Results are shown for several well-known test cases, including wave trains over a semi-circular shoal, static, and moving bottom tsunami-like wave propagation.

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Kemal Firdaus, Jörn Behrens. 2026-06-25. Two-Dimensional Locally Adaptive Non-Hydrostatic Extension of Shallow Water Equations. https://arxiv.org/abs/2606.27562

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