amerta: A Python Library for Idealized 1D Saint--Venant Dam-Break Simulation

Dasapta E. Irawan; Sandy H. S. Herho; Iwan P. Anwar; Faruq Khadami; Astyka Pamumpuni; Rendy D. Kartiko; Edi Riawan; Rusmawan Suwarman; Deny J. Puradimaja

arXiv · 2605.31011

amerta: A Python Library for Idealized 1D Saint--Venant Dam-Break Simulation

Dasapta E. Irawan·Sandy H. S. Herho·Iwan P. Anwar·Faruq Khadami·Astyka Pamumpuni·Rendy D. Kartiko·Edi Riawan·Rusmawan Suwarman·Deny J. Puradimaja

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Abstract

The Saint-Venant shallow water equations (SWE) govern depth-integrated free-surface flows arising in dam-break inundation, flood routing, tsunami runup, and estuarine tidal dynamics. Closed-form analytical solutions exist only for highly idealized Riemann configurations, making rigorously verified numerical solvers essential. This work presents amerta, an open-source Python library that solves the one-dimensional frictionless Saint-Venant system on a uniform Cartesian grid using Monotone Upstream-centered Schemes for Conservation Laws (MUSCL) reconstruction with a minmod slope limiter, the Harten-Lax-van Leer-Contact (HLLC) approximate Riemann solver, and two-stage strong-stability-preserving Runge-Kutta (SSP-RK) time integration. Numba just-in-time (JIT) compilation accelerates the performance-critical kernels. The solver is verified end-to-end against the four canonical Riemann configurations: wet-bed dam break, dry-bed dam break, double rarefaction, and double shock. A six-component post-processing pipeline quantifies space-time topology, final-time error norms with empirical quantile decomposition, self-similarity collapse onto the analytical Riemann fan, integral-norm evolution, boundary-flux-corrected mass and energy diagnostics, and phase-plane analysis against analytical wave curves. The implementation conserves discrete mass to floating-point precision, satisfies discrete entropy admissibility identically, and reproduces all four analytical wave-curve geometries to within sub-centimetre accuracy in the depth-velocity phase plane. The complete source code, analytical-solution evaluators, post-processing scripts, and Network Common Data Format (NetCDF) archives are released under the MIT license.

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Dasapta E. Irawan, Sandy H. S. Herho, Iwan P. Anwar, Faruq Khadami, Astyka Pamumpuni, Rendy D. Kartiko, Edi Riawan, Rusmawan Suwarman, Deny J. Puradimaja. 2026-05-29. amerta: A Python Library for Idealized 1D Saint--Venant Dam-Break Simulation. https://arxiv.org/abs/2605.31011

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