A Turbulence Model for Velocity Distribution in Open‐Channel Flows Through Mangrove Trees

• Published in: Water Resources Research
• Main Authors: Zerun Tang, Wei‐Jie Wang, Saiyu Yuan, Shuolin Li, Pei Xin
• Format: Article
• Language: English
• Published: Wiley 2025-08-01
• Subjects: mangrove forest; velocity profile; turbulent shear stress; co‐spectral budget; momentum transport
• Online Access: https://doi.org/10.1029/2024WR039599
• ISSN: 0043-1397; 1944-7973

Abstract The vertical distribution of flow velocity plays a critical role in sediment transport and nutrient circulation within mangrove forests, characterized by their intricate root structures. Existing velocity profile models typically rely on a single mixing length scale, limiting their ability to capture the energy distribution of turbulent eddies across multiple scales. To address this limitation, we propose a turbulence model based on the eddy energetics that incorporates multiple length scales, resolving both local and non‐local effects. The model closes the shear stress term through a co‐spectral density function, employing a modified spectral linear Rotta scheme to account for the pressure‐redistribution effect. It integrates all relevant characteristic scales by leveraging a well‐established vertical velocity spectrum that encompasses eddies from the energy‐containing and inertial ranges. Validation of the model through numerical solutions shows excellent agreement with data from both flume experiments and field observations. Additionally, an approximate analytical solution is derived under simplified conditions, which reduces to the mixing length model under restricted scenarios. These findings offer a fresh model for characterizing the hydrodynamic impact of mangrove prop roots on turbulence, with implications for understanding material mixing and transport processes in mangroves.