TY - JOUR

T1 - Numerical investigation of wave attenuation by rigid vegetation based on a porous media approach

AU - Hadadpour, Sanaz

AU - Paul, Maike

AU - Oumeraci, Hocine

N1 - Funding Information: The financial support by the Deutscher Akademischer Austauschdienst (DAAD) of this research in the frame of the PhD study by the first author is gratefully acknowledged. M. Paul acknowledges funding from the German Science Foundation (grant no. PA 2547/1-1). We do appreciate Prof. Dr. Rodolfo Silva Casarín and Prof. Dr. M. Luisa Martínez for all the time and effort they put in initiating and managing this Special Issue, and their helpful comments as Guest Editors. V. Chávez Cerón and D. Lithgow are appreciated for the time and effort they put into organizing EXCEED-SWINDON Summer School INECEP in Mexico, 2017.

PY - 2019/7/1

Y1 - 2019/7/1

N2 - Coastal areas are very complex and sensitive regions, which are extremely important in terms of economic, social and environmental values. Providing protection against coastal erosion is thus a significant issue and considerable research has been dedicated to the development of shore protection solutions. The importance of coastal vegetation and its role in wave attenuation and coastal protection in this context is still not fully understood. This study focuses on wave attenuation by coastal vegetation. For this purpose, numerical analysis is used to determine whether the vegetation field can be considered as a porous medium and whether a porous media based approach can be applied to describe the flow in a vegetation field. The computational fluid dynamic (CFD) solver ''PorousWaveFoam'' in the frame of OpenFOAM, which solves the Volume Averaged Navier-Stokes (VRANS) equations, is used for the simulation of flow in porous media. The model is calibrated and a new equivalent porosity (neq ) based on leaf area index (LAI) is developed and implemented in ''PorousWaveFoam''. The model is validated by various laboratory experiments of wave propagation through rigid vegetation, showing a good agreement between the measured and calculated wave height dissipation. It is concluded that the presented porous media approach performs well in simulating wave attenuation by a rigid vegetation field. Moreover, by using the validated model, it is confirmed that for a given water depth, wave attenuation depends on the plant characteristics (plant density, height and length of vegetation field). A higher density and longer vegetation field leads to higher attenuation rates. Wave attenuation decreases if the submergence ratio increases.

AB - Coastal areas are very complex and sensitive regions, which are extremely important in terms of economic, social and environmental values. Providing protection against coastal erosion is thus a significant issue and considerable research has been dedicated to the development of shore protection solutions. The importance of coastal vegetation and its role in wave attenuation and coastal protection in this context is still not fully understood. This study focuses on wave attenuation by coastal vegetation. For this purpose, numerical analysis is used to determine whether the vegetation field can be considered as a porous medium and whether a porous media based approach can be applied to describe the flow in a vegetation field. The computational fluid dynamic (CFD) solver ''PorousWaveFoam'' in the frame of OpenFOAM, which solves the Volume Averaged Navier-Stokes (VRANS) equations, is used for the simulation of flow in porous media. The model is calibrated and a new equivalent porosity (neq ) based on leaf area index (LAI) is developed and implemented in ''PorousWaveFoam''. The model is validated by various laboratory experiments of wave propagation through rigid vegetation, showing a good agreement between the measured and calculated wave height dissipation. It is concluded that the presented porous media approach performs well in simulating wave attenuation by a rigid vegetation field. Moreover, by using the validated model, it is confirmed that for a given water depth, wave attenuation depends on the plant characteristics (plant density, height and length of vegetation field). A higher density and longer vegetation field leads to higher attenuation rates. Wave attenuation decreases if the submergence ratio increases.

KW - Coastal vegetation

KW - Computational fluid dynamic (CFD) model

KW - Equivalent porosity

KW - Wave damping

KW - Wave-vegetation interaction

UR - http://www.scopus.com/inward/record.url?scp=85070722924&partnerID=8YFLogxK

U2 - 10.2112/si92-011.1

DO - 10.2112/si92-011.1

M3 - Article

AN - SCOPUS:85070722924

VL - 92

SP - 92

EP - 100

JO - Journal of coastal research

JF - Journal of coastal research

SN - 0749-0208

IS - 1

ER -