Author(s): Huiran Liu; Pengzhi Lin
Linked Author(s): Pengzhi Lin
Keywords: Flexible vegetation dynamics irregular waves numerical simulation wave-vegetation interaction
Abstract: Aquatic vegetation, such as salt marshes and mangroves, is commonly found in coastal and estuarine areas. The presence of this vegetation has a significant influence on reducing wave height, slowing flow velocities, altering flow structures, and modifying turbulence mixing characteristics. As a result, coastal marshes or forests can defend against coastal hazards, mitigate coastal erosion, and enhance habitat and species diversity. In natural environments, waves are often irregular, and the flexibility of vegetation cannot be overlooked. Therefore, studying the attenuation laws of irregular waves and the dynamic response of flexible vegetation is critical for understanding coastal ecological restoration and enhancing the defence of aquatic vegetation against coastal hazards. In this study, we have implemented a coupled numerical model to simulate the interaction between irregular waves and flexible vegetation. The fluid dynamics component of this model is based on the fully validated RANS model NEWFLUME (Lin & Xu, 2006), while the Flexible Vegetation Dynamics Model (FVDM) was developed using a vegetation force balance equation (Luhar & Nepf, 2016). The velocities and accelerations of the water flow, calculated from the fluid model, are introduced into the FVDM to determine the forces, movements, and deformations of the vegetation. The reaction forces exerted by the vegetation, as calculated by the FVDM, are then fed back into the fluid model to update the calculations of water flow velocities, turbulence, and wave heights. A modified k-ε closure model (Tang et al., 2021) that includes a shear production term and a wake production term was used to account for the influence of vegetation on turbulence production and dissipation. Irregular waves are generated by an adaptive internal mass source wave-maker model (Liu & Lin, 2024). This coupled model was validated against a series of experimental data, including aspects such as vegetation deformation, the force exertion process on vegetation, and wave height attenuation. Finally, this model was used to simulate irregular wave interaction with flexible vegetation on a slope. Detailed analyses were carried out on wave propagation, wave height attenuation, turbulence characteristics, and the vegetation dynamics.
Year: 2025