Moment-enhanced shallow water equations for non-slip boundary conditions

Fuente: arXiv
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Main Authors: Zhou, Shiping, Huang, Juntao, Christlieb, Andrew J.
Format: Preprint
Published: 2025
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_version_ 1866918153482665984
author Zhou, Shiping
Huang, Juntao
Christlieb, Andrew J.
author_facet Zhou, Shiping
Huang, Juntao
Christlieb, Andrew J.
contents The shallow water equations often assume a constant velocity profile along the vertical axis. However, this assumption does not hold in many practical applications. To better approximate the vertical velocity distribution, models such as the shallow water moment expansion models have been proposed. Nevertheless, under non-slip bottom boundary conditions, both the standard shallow water equation and its moment-enhanced models struggle to accurately capture the vertical velocity profile due to the stiff source terms. In this work, we propose modified shallow water equations and corresponding moment-enhanced models that perform well under both non-slip and slip boundary conditions. The primary difference between the modified and original models lies in the treatment of the source term, which allows our modified moment expansion models to be readily generalized, while maintaining compatibility with our previous analysis on the hyperbolicity of the model. To assess the performance of both the standard and modified moment expansion models, we conduct a comprehensive numerical comparison with the incompressible Navier--Stokes equations -- a comparison that is absent from existing literature.
format Preprint
id arxiv_https___arxiv_org_abs_2506_14785
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Moment-enhanced shallow water equations for non-slip boundary conditions
Zhou, Shiping
Huang, Juntao
Christlieb, Andrew J.
Numerical Analysis
Mathematical Physics
Fluid Dynamics
35L65, 65M22, 65L04
The shallow water equations often assume a constant velocity profile along the vertical axis. However, this assumption does not hold in many practical applications. To better approximate the vertical velocity distribution, models such as the shallow water moment expansion models have been proposed. Nevertheless, under non-slip bottom boundary conditions, both the standard shallow water equation and its moment-enhanced models struggle to accurately capture the vertical velocity profile due to the stiff source terms. In this work, we propose modified shallow water equations and corresponding moment-enhanced models that perform well under both non-slip and slip boundary conditions. The primary difference between the modified and original models lies in the treatment of the source term, which allows our modified moment expansion models to be readily generalized, while maintaining compatibility with our previous analysis on the hyperbolicity of the model. To assess the performance of both the standard and modified moment expansion models, we conduct a comprehensive numerical comparison with the incompressible Navier--Stokes equations -- a comparison that is absent from existing literature.
title Moment-enhanced shallow water equations for non-slip boundary conditions
topic Numerical Analysis
Mathematical Physics
Fluid Dynamics
35L65, 65M22, 65L04
url https://arxiv.org/abs/2506.14785