Dissipation of Solitary Wave Due To Mangrove Forest: A Numerical Study by Using Non-Dispersive Wave Model

Abstract

In this paper, we study a dissipation of solitary wave due to mangrove forest by using numerical simulation. Here, the solitary wave is chosen to represent tsunami wave form. To simulate the wave dynamic, we use the non-dispersive Nonlinear Shallow Water Equations (NSWE). The model is implemented numerically by using finite volume method in a momentum conservative staggered grid. By using the proposed numerical scheme, the numerical code is able to simulate solitary wave breaking phenomenon. Wave dissipation due to mangrove forest is modelled as bottom roughness with an approximate value of manning roughness, which is derived from the classical Morisson’s formula. To test the modelled dissipation by mangrove forest, we reconstruct a physical experiment in hydrodynamic laboratory where a solitary wave propagates above a sloping bottom, which has a parameterized mangrove in the shallower part. Two cases are performed to test the performance of the numerical implementation, i.e. the non-breaking and breaking solitary waves. Results of simulation agree quite well with the measurement data. The results of simulation are also analyzed quantitatively by calculating errors as well as correlation with the measurement data. Moreover, to investigate effects of wave steepness on solitary wave, to the reduction of wave energy, we perform numerical investigation. Various solitary waves with different wave steepness are simulated to see their effects on amplitude and energy reduction due to mangrove forest.

Staggered Numerical Modeling for Investigating the Effectiveness of Embankment and Vegetation on the Reduction of Wave Run-up

“…In this article, the vegetation is considered as a friction term by adding Manning friction to the governing equations directly. Following Aditya in [1] and Gunawan [10], the Manning friction is given in Equation 3. Influence of the shoreline is cosidered in the bottom topography ( ).…”

“…Following another research in [1], discretization of the Manning friction term (see Equation 3is written as…”

“…Numerical modeling on each case (embankment or vegetation only) can be found in many references for instances see [1], [2] for the vegetation modeling and [3], [4] for the embankment modelling. In the work of Adytia et al in [1], the model is based on shallow water equations with Manning friction. The model was solved numerically using staggered conservative scheme.…”

Pendekatan Numerik Disipasi Gelombang Reguler Oleh Hutan Mangrove Menggunakan Model Dispersif Boussinesq

“…Penelitian mengenai dampak redaman gelombang tsunami oleh hutan mangrove telah banyak dilakukan, baik secara eksperimen fisik maupun melalui simulasi numerik (Ismail et al, 2012;Dahdouh-Guebas et al, 2005;Adytia dan Husrin, 2019;Adytia et al, 2019a). Secara numerik, penelitian tentang redaman gelombang oleh hutan mangrove dapat menggunakan model gelombang yang relatif sederhana, yaitu 2 SWE yang valid untuk menyimulasikan gelombang panjang (Adytia et al, 2019a). Pada SWE, variasi kecepatan pada arah vertikal fluida diabaikan.…”

“…Model gelombang ini diimplementasikan secara numerik dengan menggunakan metode Finite Volume pada skema staggered grid (Adytia et al, 2019b). Model redaman gelombang oleh hutan mangrove dimodelkan dengan memilih suatu koefisien redaman Manning yang berkorespondensi dengan koefisien drag hutan mangrove (Adytia et al, 2019a). Model numerik yang dibangun kemudian divalidasi dengan menggunakan data eksperimen dari laboratorium hidrodinamika oleh (Husrin et al, 2012).…”