Tsunami wave interaction with mangrove forests: A 3-D numerical approach

ABSTRACT: A three dimensional numerical approach based on IHFOAM to study the interaction of tsunami waves with mangrove forest is presented. As a first approximation, the problem is modelled by means of solitary waves impinging on emergent rigid cylinders. Two different conceptual approaches are implemented into IHFOAM. Solving the URANS equations provides a direct simulation of the flow field considering the actual geometry of the array of cylinders. A modified version of the volume-average URANS equations by introducing a drag force to model the momentum damping created by the cylinders is used in the second approach. Both the direct and macroscopic simulations are validated against laboratory experiments for wave damping with very high agreement. A large set of numerical experiments to analyse flow parameters and uniform and random cylinder array distributions are analysed and use to compare pros and cons of the different approaches. Large differences are found in the forces exerted on the vegetation for uniform and random distributions. Generalizations obtained from uniform arrangements could lead to underestimation of wave-exerted forces, especially for low dense configurations. Wave forces calculated with the macroscopic approach by means of the drag coefficient yields clear underestimations.M. Maza is indebted to the MEC (Ministerio de Educación, Cultura y Deporte, Spain) for the funding provided in the FPU (Formación del Profesorado Universitario) studentship (BOE-A-2012-6238). This work has been partially funded under the RETOS program of the Spanish Ministry of Economy and Competitiveness (BIA2014-59718)

Flow Interaction with Natural Structures: a Case Study of a Model

This work has been funded under the RETOS INVESTIGACION 2014 (grant BIA2014-59718-R) program of the Spanish Ministry of Economy and Competitiveness. M. Maza is indebted to the Spanish Ministry of Science, Innovation and Universities for the funding provided in the grant Juan de la Cierva Incorporación (BOE de 27/10/2017)

Wave attenuation modelling by submerged vegetation: ecological and engineering analysis

The correct address of wave characteristics in the vicinity of submerged vegetation is crucial to perform an ecological analysis. Although several attempts have been done in the past using an analytical approach or depth averaged models, the rigidity of the assumptions used to solve the physics produced limited application to real cases. The use of a NS model called IH-2VOF is used first to minimize the number of predefined assumptions for wave propagation and the non-linear interactions between waves and plants and second to explore the possibility to improve existing turbulence models to consider wave interaction with vegetation. The IH2-VOF model has been validated using large scale experiments developed by Stratigaki et al. (2011). The model has shown a high degree of accordance between the lab data and the numerical predictions in free surface evolution. Numerical predictions of the velocity field have been compared both over and inside the vegetation showing also a high degree of accordance. Drag coefficients obtained during the model calibration are in accordance with previous studies such as Mendez et al. (1999). The influence of wave height, wave period, water depth and patch density have been studied using additional numerical simulations with irregular waves. Both the wave period and the water depth have been revealed as the most important parameters in the modification of the flow patterns around the patch

Caracterización de la protección costera proporcionada por ecosistemas naturales a partir de ensayos de laboratorio y modelado numérico

Este trabajo ha sido financiado por el programa RETOS INVESTIGACION 2014 (BIA2014-59718-R) del Ministerio de Economía y Competitividad del Gobierno de España

Wave Attenuation by Spartina Saltmarshes in the Chesapeake Bay Under Storm Surge Conditions

This material is based upon work supported by the National Fish and Wildlife Foundation and the U.S. Department of the Interior under grant 43932.This material is also based upon work supported by the National Science Foundation under grant SES‐1331399.This research was also supported in part by the Thomas F. and Kate Miller Jeffress Memorial Trust, Bank of America, Trustee. M. Maza, J.L. Lara, and I.J. Losada are indebted to the Spanish Ministry of Economy and Competitiveness for the funding provided in the RETOS INVESTIGACION 2014 (grant BIA2014‐59718‐R) grant program

Integrated drag coefficient formula for estimating the wave attenuation capacity of Rhizophora sp. mangrove forests

Recently, bulk drag coefficient (~CD) formulations used to quantify wave energy dissipation by Rhizophora mangroves were developed from laboratory data; however, these formulations have not yet been validated with field data. Additionally, due to the complex geometry of mangrove trees within forests and spatial variability, common criteria for determining the adequate geometric characteristics of mangrove forests are lacking and are required to obtain accurate definitions for ~CD. This paper addresses these knowledge gaps by proposing a newly integrated ~CD formulation based on the comprehensive characterization of a Rhizophora mangle forest combined with wave measurements in field, and by using numerical modeling for the calibration process. The field campaign consisted of 23 continuous days of recorded wave data and spatial distribution observations of the geometric characteristics of the mangrove forest. The variation in frontal area per unit height per square meter (Ahm) along the mangrove forest was reported for three zones with different densities identified along the study transect, with decreasing root density from the vegetation edge to the forest interior. On average, the incident wave height decreased by 34% at 63 m in mangrove forests, and the wave attenuation ratios (r) varied between 0.001 and 0.01 m-1. To estimate the ~CD values associated with these wave height attenuation ratios, the Simulating Waves Nearshore (SWAN) numerical model was used to calibrate the model results with the field observations. The variation in the tree frontal area along the mangrove forest and the wave conditions at the site are considered during the calibration process. To further characterize ~CD for this type of mangrove species, the ~CD values acquired from the calibration together with the values reported in the literature from laboratory experiments are presented as a function of the Keulegan-Carpenter number (KC). Root diameter is defined as the characteristic length according to the inherent geometric characteristics of a Rhizophora sp. forest. The new formulation allows us to predictably estimate ~CD values that can be used as inputs in drag force-based models to estimate the attenuation of wave energy produced by Rhizophora sp. forestsThe author(s) declare financial support was received for the research, authorship, and/or publication of this article. FL-A was supported by the University of Costa Rica (scholarship OAICE 26- 2020). Grant TED2021-130804B-I00 of the project funded by MCIN/AEI/10.13039/501100011033 and by the “European Union NextGenerationEU/PRTR”. Grant PDC2022-133579-I00 of the project funded by MCIN/AEI/10.13039/501100011033 and by the “European Union NextGenerationEU/PRTR”. This study also forms part of the ThinkinAzul programme and was supported by Ministerio de Ciencia e Innovación with funding from Union NextGeneration EU (PRTR-C17.I1) and by Comunidad de Cantabri

Forces induced on a vertical breakwater by incident oblique waves

Over the last years Navier-Stokes numerical models have been developed to accurately simulate wave interaction with all kinds of coastal structures, focusing on both functionality and stability of coastal structures. Although several models have been used to simulate wave interaction with coastal structures in two dimensions (2DV) there are a vast number of three-dimensional effects that need to be investigated in order to improve the design. In this paper a new model called IH-FOAM has been applied to study a vertical breakwater at prototype scale. As a first attempt of validation, the model has been used to simulate a regular wave train generated with a relative angle with the breakwater inducing three-dimensional wave patterns not only seaward the structure due to reflection but also generating an overtopping discharge variation along the breakwater trunk. Pressure laws and overtopping discharge at three different cross-sections along the structure have been studied. The pressure laws have been compared with classical Goda’s formulation. Although, the numerical model predictions are in accordance with Goda’s calculations, a clear three-dimensional variability of wave-induced pressure has been observed. Moreover, an additional study has been performed calculating pressure laws on the side-wall at the breakwater head. Large three-dimensional effects are detected from the simulations due to the flow separation at that area. Overtopping model predictions have been compared with Overtopping Manual calculations showing very close values along the trunk. However, lower overtopping discharge values are observed at the breakwater head. This paper is a preliminary work to show the range of applicability of a three-dimensional Navier-Stokes model to study wave interaction with a vertical breakwater under the action of an oblique wave train

Modelado numérico de la interacción Fluido-Sedimento con fondo variable mediante CFD. Aplicación a la morfodinámica costera.

Este proyecto de investigación está financiado por el Ministerio de Ciencia, Investigación y Unniversidades de España a través de una beca FPU concedida al primer autor