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ORIGINAL RESEARCH article

Front. Mar. Sci.

Sec. Coastal Ocean Processes

Volume 12 - 2025 | doi: 10.3389/fmars.2025.1601009

This article is part of the Research TopicInnovations in Coastal Morphodynamic ModelingView all 4 articles

Cell division method for numerical simulation of wetting and drying in hydrodynamic models with unstructured grids

Provisionally accepted
Lirong  YuanLirong Yuan*Li-Rong  YuanLi-Rong Yuan*
  • School of Marine Sciences, Sun Yat-sen University, Zhuhai Campus, Zhuhai, China

The final, formatted version of the article will be published soon.

Periodic wetting and drying occur extensively in many shallow water systems such as coastal wetlands. Proper description of the wetting and drying front (WDF) is a challenge for hydrodynamic models of these systems and yet it is essential for accurate simulations of flow and transport processes within them. In this study, we developed an wetting and drying algorithm with cell division method to track the WDF on threedimensional unstructured grids of a finite volume-based hydrodynamic model. An inundation function was introduced to determine intersections of the moving WDF with sides of elements at the boundary. These front-associated, partially wetted elements were simulated simultaneously with fully wetted elements with full consideration of the WDF's movement and its influence on local mass and momentum balance so as to guarantee the overall flow continuity and mass conservation. Test simulations with benchmark cases were conducted to compare the performances of the new algorithm and a traditional method. The results demonstrated the improvement achieved by the improved method in terms of mass conservation, and proper simulations of the WDF and bed friction effects in near-front areas. The improved method exhibits superiority in dealing with high-order nonlinear flow and transport processes in coastal salt marsh system because it solves momentum equations in partially wetted cells. Although it was implemented within a finite-volume model, the improved algorithm, in principle, can be applied to hydrodynamic models based on other numerical methods.

Keywords: Wetting and drying, hydrodynamic modelling, moving boundary, Coastal wetland, Coastal hydrodynamics

Received: 27 Mar 2025; Accepted: 22 Sep 2025.

Copyright: © 2025 Yuan and Yuan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Lirong Yuan, yuanlr@mail.sysu.edu.cn
Li-Rong Yuan, yuanlr@sysu.edu.cn

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