Wave Transmission Coefficients Research Articles

Wave attenuation by multiple slotted barriers with a zig-zag arrangement -A physical and numerical approach

In the present study, scattering of surface gravity waves by multiple slotted vertical barriers arranged in a zig-zag manner is analyzed by employing Computational Fluid Dynamics (CFD) and validated with physical model tests. The porosity of the vertical slotted barrier is varied from 10% to 40%, and the number of slotted barriers varied from 1 to 6. The results from CFD correlate well with the laboratory measurements on the scattering coefficients for a wide range of input conditions giving a high level of confidence. For relatively short waves (h/λ > 0.3, h- water depth and λ- wave length), slotted barriers up to 3 numbers and porosity from 20% to 30% are required to achieve wave transmission coefficient in the range of 0.2 to 0.3. For relatively long waves (h/λ < 0.3), slotted barriers of 5 to 6 numbers and porosity in the range of 10% to 20% are needed to obtain wave transmission of 0.2 to 0.3. The results presented in this study can be used for a wide range of wave damping applications in the field of coastal engineering.

Fano resonances in an electrical lattice

We study the scattering properties of an electrical lattice consisting of a one-dimensional array of inductively-coupled LC units. For an initially localized electrical excitation, and in the absence of any impurity, we compute in closed form the mean square displacement of an initially localized electrical excitation for the cases of an infinite and semi-infinite lattice, obtaining a ballistic propagation under very general conditions. For the transport of extended excitations, we compute in closed form the transmission coefficient of electro-inductive plane waves across an impurity region, containing a number of side-coupled units, or a single internal impurity in the presence of coupling to first-and second nearest neighbors, looking for the presence of Fano resonances (FRs). For all cases examined, we obtain a closed-form expression for the position of the FR in terms of the relative strengths of the inductive couplings involved. For the case of two, identical side-coupled impurities, the position of the single FR turns out to be independent of the relative distance between the two impurities.

Damage Analysis of Chemically Corroded Sandstone Under Cyclic Impacts and Axial Static Pressure

To explore the influence of cyclic impact and axial static pressure on the damage of chemically corroded sandstone, a series of cyclic impact tests were conducted on white sandstone by using the Split Hopkinson Pressure Bar. Besides, the longitudinal sections and fractures of samples were observed with the scanning electron microscope for the purpose of investigating the damage characteristics and structural changes of sandstone subjected to the coupling of force and chemistry. The results show: (1) When pH of the solution is 7, the number of cyclic impacts and stress peaks of specimens increases, and the specimens respond with a significantly high resistant strength. (2) The stress wave transmission coefficient of sandstone decreases gradually with the increase of the number of cyclic impacts, while the reflection coefficient shows a tendency of "decreasing firstly and then increasing". (3) Cylindrical specimens with a certain axial static pressure present an "X" shaped conjugate failure under cyclic impact. When axial static pressure is too large or there is excessive impact, the "X" shaped conjugate undergoes shear to a state of broken cones. (4) The vertical section and fracture surface damage degree of white sandstone soaked in the sodium sulfate solution is more serious than that in the sodium sulfate solution.

Analytical Approach of Wave Transmission Coefficient through on Composite Hanging Breakwater

Conventional breakwater like a rubble mount is require large infestation, especially when that structure construct in deep water. Currently, innovations are needed to solve financial problems in building breakwaters. Composite hanging breakwater is proposed as a new solution in marine structure. Composite hanging breakwater made by both of stone and concrete or steel material consist of two-part are structural part and filler. Structural parts are piles, beams, and brackets made of concrete or steel. Filler material using of stone or other material. This structure has the advantage are cheaper than conventional breakwater, precast material, and the diameter of stone filler is relatively small. Until now, the performance of composite hanging breakwater is unknown. Commonly, the key performance indicator of breakwaters is wave transmission and represent by the waves transmission coefficient. Therefore, in this study, an analytical equation of wave transmission coefficient was developed using the conservation of energy concept. Based on this equation shows that the wave transmission coefficient is influenced by both structure and wave parameter. After the equation has been obtained, then it is compared with previous research. Research that has been used as a comparison includes research by Weigel (1960), Abul-Azm (1993), Liu and Abbaspour (1982), Abu-Azm (1993), Heikal (1997), Koraim (2005), Rage and Koraim (2010), and Koraim (2014). Wave parameter represents by waves steepness implicitly, and structure parameter is represented by the permeability of structure, relative length, and relative depth. The greater the value both of relative depth and length, the smaller value of wave transmission coefficient. The greater the value of structure permeability, the smaller the value of wave transmission coefficient. When the D/h is zero, the wave transmission coefficient is equal to one and when the D/h is equal to one, the transmission coefficient is close to or equal to zero. When the D/h value is less than 0.5, the Kt value in this present study is lower than the Kt value in previous studies for the same D/h value, and when the D/h value is greater or equal to 0.5 then the Kt value is close or the same with the previous study.

Wave energy dissipation through a hollow triangle breakwater on the coastal Mekong Delta

The Vietnamese Mekong Delta (VMD) has suffered from a number of significant environmental issues, including coastline erosion. This study introduces a new structure of Hollow Triangle Breakwaters (HTB) to protect the coastline, stimulate sedimentation and restore mangrove forests along the Mekong Delta coastline. The hydraulic parameters of the HTB were studied and tested on physical models. These experiments included changing a range of parameters including the porosity of the surface, wave parameters and water level to determine the optimal porosity (KH2) for wave transmission, reflection and wave dissipation. The results showed that the reflection coefficient is inversely proportional to the breakwater porosity screen. The transmission coefficient for a non-overtopped breakwater depends on the breakwater porosity screen on both sides of the HTB. The coefficient of wave energy dissipation is highest when the porosity on the seaside is larger than on the shoreside of the breakwater, particularly in the optimal porosity case (KH2). It is recommended to design the HTB breakwater working under the emerged state (Rc/Hm0, i > 0.5) for the best wave reduction efficiency. The study also compared hydraulic parameters of different types of breakwaters with different shapes and it was found that the porous structures significantly affected the wave transmission coefficient, reflected and dissipation coefficients. The comparison between field measurement and experiment results declares that the HTB structure is able to transmit the long wave passing through the breakwater at a certain level, and dissipates most of the shortwave energy. This facilitates the sedimentation and mangroves restoration in the shoreside area which indicates that the HTB has a significant potential to reduce coastline erosion in the VMD.

Prediction of Wave Transmission Characteristics of Low-Crested Structures with Comprehensive Analysis of Machine Learning.

The adoption of low-crested and submerged structures (LCS) reduces the wave behind a structure, depending on the changes in the freeboard, and induces stable waves in the offshore. We aimed to estimate the wave transmission coefficient behind LCS structures to determine the feasible characteristics of wave mitigation. In addition, various empirical formulas based on regression analysis were proposed to quantitatively predict wave attenuation characteristics for field applications. However, inherent variability of wave attenuation causes the limitation of linear statistical approaches, such as linear regression analysis. Herein, to develop an optimization model for the hydrodynamic behavior of the LCS, we performed a comprehensive analysis of 10 types of machine learning models, which were compared and reviewed on the prediction accuracy with existing empirical formulas. We found that, among the 10 models, the gradient boosting model showed the highest prediction accuracy with MSE of 1.0 × 10−3, an index of agreement of 0.996, a scatter index of 0.065, and a correlation coefficient of 0.983, which indicates a performance improvement over the existing empirical formulas. In addition, based on a variable importance analysis using explainable artificial intelligence, we determined the significant importance of the input variable for the relative freeboard (RC/H0) and the relative freeboard to water depth ratio (RC/h), which confirms that the relative freeboard was the most dominant factor for influencing wave attenuation in the hydraulic behavior around the LCS. Thus, we concluded that the performance prediction method using a machine learning model can be applied to various predictive studies in the field of coastal engineering, deviating from existing empirical-based research.

Hydrodynamic Performance of a Multi-Module Three-Cylinder Floating Breakwater System under the Influence of Reefs: A 3D Experimental Study

As the technical and theoretical research of floating breakwaters is becoming increasingly mature, the floating breakwaters are now being utilized, especially in offshore reefs. Therefore, it is of practical significance to study the hydrodynamic performance of a multi-module floating breakwater system under the influence of reefs. In this study, a 3D model experiment was carried out on a system consisting of eight three-cylinder floating breakwater modules under the influence of reefs. A wave attenuation mesh cage was incorporated at the bottom of the model. The floating breakwater system was slack-moored in its equilibrium position, and each module was connected by elastic connectors. The reefs were modeled on a bathymetric map of existing reefs in the East China Sea. In this experiment, the wave transmission coefficients, motion responses, and mooring forces of the floating breakwater system were measured. The results showed that the three-cylinder floating breakwater in the beam waves (β = 90°) has excellent wave attenuating performance under the influence of reefs, especially for short-period waves. However, under the influence of the reef reflection wave and the shallow water effect, the motion responses in the three main stress directions of the floating breakwater were large, and there was some surge and pitch motion. Under the influence of the aggregation and superposition of reflected waves on both sides of the reefs, the peak mooring forces in the middle position of the floating breakwater system were the largest at large wave height. The three-cylinder floating breakwater exhibited satisfactory hydrodynamic performance under the influence of reefs. It has broad application prospects in offshore reefs.

Calculation of reflection and transmission coefficients for waves in multilayered piezoelectric structures using the mixed variable method.

The reflection and transmission (R/T) behavior of elastic waves in an anisotropic multilayered piezoelectric structure bounded by two homogeneous half-spaces is studied using the mixed variable method. The mixed variable method, which is based on the mixed energy matrix, takes the displacement vector at one end of the structure and the stress vector at other end of the structure as the basic variables. The wave equation for a homogeneous piezoelectric layer is transformed into a first-order state equation in the Hamiltonian system by introducing a dual vector. The general solution of the state equation can be expressed in terms of the eigenvalues and eigenvectors of the complex Hamiltonian matrix. A mixed energy matrix is applied to establish the relationship between the generalized displacement and stress vectors on the upper and lower interfaces of a layer. By an efficient recursive algorithm, the global mixed energy matrix is formed for an arbitrarily anisotropic multilayered piezoelectric structure. The R/T coefficients of the waves in an anisotropic multilayered piezoelectric structure are derived by the global mixed energy matrix. Numerical examples are provided to show the robustness of the mixed variable method. The effects of the incident angles, wavenumbers, and critical angles on the R/T coefficients are discussed.

Scattering of water waves by rectangular thick barriers in presence of surface tension

The influence of surface tension over an oblique incident waves in presence of thick rectangular barriers present in water of uniform finite depth is discussed here. Three different structures of a bottom-standing submerged barrier, submerged rectangular block not extending down to the bottom and fully submerged block extending down to the bottom with a finite gap are considered. An appropriate multi-term Galekin approximation technique involving ultraspherical Gegenbauer polynomial is employed for solving the integral equations arising in the mathematical analysis. The reflection and transmission coefficients of the progressive waves for two-dimensional time har- monic motion are evaluated by utilizing linearized potential theory. The theoretical result is validated numerically and explained graphically in a number of figures. The present result will almost match analytically and graphically with those results already available in the literature without considering the effect of surface tension. From the graphical representation, it is clearly visible that the amplitude of reflection coefficient decreases with increasing values of surface tension. It is also seen that the presence of surface tension, the change of width, and the height of the thick barriers affect the nature of the reflection coefficients significantly

Bamboo Fences as a Nature-Based Measure for Coastal Wetland Protection in Vietnam

Climate change has induced sea-level rise and a high intensity of storms, which create high nearshore waves. These caused severe mangrove degradation and erosion along the coastal wetland areas in the Mekong Delta in Vietnam. Mangroves in the coastal wetland foreshore can withstand only some certain design storm waves and grow under several certain submerged conditions. Therefore, reducing waves and shallowing wetland elevation for recovering mangroves and protecting them in an early birth state is important. Bamboo or melaleuca fences have been used as a nature-based solution to reduce waves and currents approaching the shore for these above purposes along Vietnamese Mekong deltaic coasts. This paper investigates wave transmission through the bamboo fence system and assesses its effectiveness in protecting the mangroves. Waves were simultaneously measured at two locations for comparison: in front of and behind the fences. The result shows that the wave reduction by the fences is considerable, and sedimentation occurs rapidly in the shelter areas behind the fences, which is highly favorable for the recovery and growth of mangroves. Next, the empirical formulae have been proposed for relationships between the wave transmission coefficient of the fence and the dimensionless wave-structures parameters, such as the relative water depth, the wave steepness, and the fence freeboard. The findings create a basic technical reference for designing a naturally friendly-based solution by using bamboo and/or wooden fences in coastal protection generally and protecting mangroves specifically. The outcome of the research contributes to narrowing an existing gap in Vietnamese design guidelines for coastal wetland protection and also facilitates the use of locally available eco-friendly materials for coastal management along the Vietnamese Mekong delta coasts.

Variation of Irregular Waves Passing Over an Artificial Coral Reef (ACR)

Hong, S.; Dodaran, A.A.; Kim, T.; Kim, J.; Huynh, V.M.; Lee, J., and Kwon, S., 2021. Variation of irregular waves passing over an Artificial Coral Reef (ACR). In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 524–528. Coconut Creek (Florida), ISSN 0749-0208. To investigate the variation of irregular waves due to an Artificial Coral Reef (ACR), two-dimensional experiments on the wave steepness, wave period, and relative submergence were conducted. The results for the wave transmission coefficient under ACR installation indicated that the wave steepness and period conditions are closely related to wave attenuation, which has similar trends for general coastal structures, even under irregular wave conditions. Additionally, the total spectral energy decreased gradually, whereas an inconsistent peak-energy decrement occurred with a wave steepness of 0.032, which was expected because of spectral energy redistribution due to ACR. The correlation between the relative submergence and spectral energy was investigated via a spectral analysis. In high frequency domain (1.25∼2.25f/fp), the composition ratio of spectral energy increased with larger relative submergence, whereas opposite trend was observed in low frequency domain (0.25∼0.75f/fp). The main findings of this study can provide basic knowledge for understanding irregular wave variation over the ACR.

Coupled analytical-numerical approach for determining hydrodynamic responses of breakwater with multiple OWCs

A coupled analytical-numerical approach has been developed that allows one to study the hydrodynamic responses of breakwaters of arbitrary geometry that have multiple OWCs with horizontal openings. The approach incorporates the eigenfunction of the OWC fluid domain into the boundary element method, which automatically satisfy the boundary condition at the OWC opening. As a result, the exact geometry of the OWCs no longer needs to be modelled and the number of elements will be largely reduced especially when dealing with 3D breakwaters. With the present approach, a class of 2D OWC-integrated breakwater concepts in existing literature was simulated for validation and parametric study. The approach was then applied to the 3D breakwater with multiple OWCs under slender OWC assumptions, and the numerical results obtained are compared to data from a reduced scale model test. The 2D case studies show that the present approach is able to generate accurate results on reflection and transmission, wave loads, and energy extraction efficiencies with a higher efficiency than conventional boundary element method. Comparison of 3D results with the model test results shows that the prediction of the natural frequency and the wave reflection and transmission coefficients are in good agreement.

Numerical Study on the Hydrodynamic Characteristics of a Double-Row Floating Breakwater Composed of a Pontoon and an Airbag

By adding a cylindrical airbag on the leeward side of a cuboid pontoon, a new-type double-row floating breakwater is designed to improve the wave attenuation performance, and its hydrodynamic characteristics are studied through numerical simulations. First, based on the smoothed particle hydrodynamics (SPH) method, a numerical model used to simulate the interaction between waves and moored floating bodies is built. The fluid motion is governed by the Navier–Stokes equations. The motion of the floating body is computed according to Newton’s second law. The modified dynamic boundary condition is employed to treat the solid boundary. The lumped-mass method is adopted to implement the mooring system. Then, two physical model experiments on waves interaction with cuboid and dual cylindrical floating pontoons are reproduced. By comparing the experimental and numerical wave transmission coefficients, wave reflection coefficients, response amplitude operators and mooring force, the reliability of the numerical model is validated. Finally, the validated numerical model is applied to study the influence of separation distance and wave parameters on the hydrodynamic characteristics of the double-row floating breakwater. The results indicate that the optimal separation distance between pontoon and airbag is 0.75 times the wavelength. At such separation distance and within the concerned 1–4 m wave heights and 4–7 s wave periods, the pontoon-airbag system presents better wave attenuation performance than a single pontoon. This improvement weakens as wave height increases while it strengthens as the wave period increases. In addition, the double-row floating breakwater is more effective in a high-wave regime than in a low-wave regime. In the case of short waves, attention should be paid to the stability and mooring reliability of the seaward pontoon, while in the case of long waves, care needs to be taken of the leeward airbag.

A Numerical Simulation of Blasting Stress Wave Propagation in a Jointed Rock Mass under Initial Stresses

The initial stresses have a strong effect on the mechanical behavior of underground rock masses, and the initial stressed rock masses are usually under strong dynamic disturbances such as blasting and earthquakes. The influence mechanism of a blasting excavation on underground rock masses can be revealed by studying the propagation of stress waves in them. In this paper, the improved Mohr-Coulomb elasto-plastic constitutive model of the intact rock considering the initial damage was first established and numerically implemented in Universal Distinct Element Code (UDEC) based on the variation of the experimental stress wave velocity in the initial stressed intact rock, and the feasibility of combining the established rock constitutive model and the BB (Bandis-Barton) model which characterizes the nonlinear deformation of the joints to simulate stress waves across jointed rock masses under initial stress was validated by comparing the numerical and model test results subsequently. Finally, further parameter studies were carried out through the UDEC to investigate the effect of the initial stress, angle, and number of joints on the transmission of the blasting stress wave in the jointed rock mass. The results showed that the initial stress significantly changed the propagation of the stress waves in the jointed rock mass. When the initial stress was small, the transmission coefficients of the stress waves in the jointed rock were vulnerable to be influenced by the variation of the angle and the number of joints, while the effect of the angle and the number of joints on the stress wave propagation gradually weakened as the initial stress increased.

EFFECT OF SEDIMENT MODEL ON DYNAMIC PRESSURES OF SUBMERGED FLOATING TUNNEL DUE TO SV WAVE INCIDENCE

To study the dynamic pressure acting on the submerged floating tunnel (SFT) under the seismic SV wave in complex seawater environment, a theoretical analysis model is proposed considering the marine sediment effect. Based on the wave equations and displacement potential functions of different media materials, the theoretical equations of wave transmission and reflection coefficients at different interfaces are deduced and solved on MATLAB through the seismic SV wave propagation boundary. Numerical examples are employed to illustrate the effects of the saturation of the sediment, the incident SV-wave angle and the layout of tether on the dynamic pressure on the SFT. The results show that the unsaturated sediment has greater effect on the dynamic pressure on the SFT than that of the saturated sediment. Thicker sediment is more benefit to the SFT under the action of seismic SV wave. And increasing the tether stiffness or decreasing the tether spacing can reduce the dynamic pressure on the SFT.

Modeling and Imaging of Ultrasonic Array Inspection of Side Drilled Holes in Layered Anisotropic Media.

There has been an increase in the use of ultrasonic arrays for the detection of defects in composite structures used in the aerospace industry. The response of a defect embedded in such a medium is influenced by the inherent anisotropy of the bounding medium and the layering of the bounding medium and hence poses challenges for the interpretation of the full matrix capture (FMC) results. Modeling techniques can be used to understand and simulate the effect of the structure and the defect on the received signals. Existing modeling techniques, such as finite element methods (FEM), finite difference time domain (FDTD), and analytical solutions, are computationally inefficient or are singularly used for structures with complex geometries. In this paper, we develop a novel model based on the Gaussian-based recursive stiffness matrix approach to model the scattering from a side-drilled hole embedded in an anisotropic layered medium. The paper provides a novel method to calculate the transmission and reflection coefficients of plane waves traveling from a layered anisotropic medium into a semi-infinite anisotropic medium by combining the transfer matrix and stiffness matrix methods. The novelty of the paper is the developed model using Gaussian beams to simulate the scattering from a Side Drilled Hole (SDH) embedded in a multilayered composite laminate, which can be used in both immersion and contact setups. We describe a method to combine the scattering from defects with the model to simulate the response of a layered structure and to simulate the full matrix capture (FMC) signals that are received from an SDH embedded in a layered medium. The model-assisted correction total focusing method (MAC-TFM) imaging is used to image both the simulated and experimental results. The proposed method has been validated for both isotropic and anisotropic media by a qualitative and quantitative comparison with experimentally determined signals. The method proposed in this paper is modular, computationally inexpensive, and is in good agreement with experimentally determined signals, and it enables us to understand the effects of various parameters on the scattering of a defect embedded in a layered anisotropic medium.

Performance evaluation of submerged breakwater using Multi-Domain Boundary Element Method

The gravity wave interaction with submerged breakwater of different structural configurations are investigated based on the small-amplitude wave theory. The boundary value problem is analysed in two-dimension using the linearized wave theory in water of finite depth. The submerged breakwater structural configuration such as (i) thin-walled type (impermeable), (ii) rectangular type (impermeable and permeable), (iii) triangular type (impermeable, permeable, perforated), (iv) trapezoidal type (impermeable, permeable, perforated) and (v) Tandem type (impermeable, permeable, perforated) are considered to analyse and performance of the breakwater. The numerical model is developed using the Multi-Domain Boundary Element Method (MDBEM) to analyse the hydrodynamic scattering coefficient (such as reflection, transmission and dissipation coefficient) for the change of physical parameters such as relative spacing between the breakwaters, relative water depth and structural dimensions. The convergence of the present numerical model is performed for the specific case of tandem breakwater and numerical computation is validated with the results available in the literature. The wave reflection and transmission coefficient along with wave force on the structure is analysed for different shapes, structural parameters and geometrical parameters of the breakwater to maximize the efficiency of breakwater. In the case of permeable breakwater, the submerged tandem breakwater is found to be more efficient in wave transformation as compared to rectangular, triangular and trapezoidal permeable submerged breakwaters. The comparative analysis performed on different configurations of the breakwater in the present study will be helpful in the effective design of the breakwater near the harbour regions.

Hydrodynamic Performance of an Asymmetry OWC Device Mounted on a Box-Type Breakwater

To share the construction and maintenance cost, an asymmetric oscillating water column (OWC) device integrated with a pile-fixed box-typed offshore breakwater is considered experimentally and numerically. A fully nonlinear numerical wave tank is established and validated with the open source solver OpenFOAM. The effects of the width and draft of rear box, and the incident wave height on the wave energy conversion efficiency, reflection and transmission coefficients, and energy dissipation coefficient are examined. In addition, the superiority of the present coupling system, compared to the traditional box-type breakwater, is discussed. With well comparisons, the results show that the existence of the rear breakwater is beneficial for the formation of partial standing waves and further wave energy conversion. In the range of wave heights tested, the higher the incident wave height, the larger the energy absorption efficiency except for the short-wave regimes. Moreover, the OWC-breakwater coupling system can obtain a similar wave blocking ability to the traditional one, and simultaneously extract wave energy and decrease wave reflection.

Hydrodynamic Performance Improvement of Double-Row Floating Breakwaters by Changing the Cross-Sectional Geometry

This paper is presented to develop the hydrodynamic performance of double-row floating breakwater (FBW) by changing cross-sectional geometry in the high wave periods. The ANSYS-AQWA software is employed for the present calculations, which is a potential-based boundary element method (BEM). The rectangular moored pontoons in the single- and double-row types are selected, and the results of the wave transmission coefficient and response amplitude operator (RAO) are presented and compared. The numerical results showed good agreement with experimental data at different wavelengths, wave height, and the distance between double-row FBWs. Then, the performance results of FBWs for five shapes (rectangular, π-shaped, plus-shaped, triangular-shaped, and box-shaped) in the wave transmission coefficient, RAO, and mooring line tension are presented and compared to each other. The results showed that the plus-shaped FBW has a better performance in reducing wave transmission than other shapes. In waves with long periods, the performance of π-shaped, triangular-shaped, and box-shaped FBWs is reduced, and the rectangular FBW loses its efficiency. Overall, the plus-shaped FBW has preferable performance regarding RAO response, mooring tension, and wave transmission.

1D–2D Numerical Model for Wave Attenuation by Mangroves as a Porous Structure

In this paper, we investigate wave attenuation caused by mangroves as a porous media. A 1-D mathematical model is derived by modifying the shallow water equations (SWEs). Two approaches are used to involve the existing of mangrove: friction term and diffusion term. The model will be solved analytically using the separation of variables method and numerically using a staggered finite volume method. From both methods, wave transmission coefficient will be obtained and used to observe the damping effect induced by the porous media. Several comparisons are shown to examine the accuracy and robustness of the derived numerical scheme. The results show that the friction coefficient, diffusion coefficient and vegetation’s length have a significant effect on the transmission coefficient. Moreover, numerical observation is extended to a 2-D SWEs, where we conduct a numerical simulation over a real bathymetry profile. The results from the 2-D numerical scheme will be validated using the data obtained from the field measurement which took place in Demak, Central Java, Indonesia. The results from this research will be beneficial to determine the characteristics of porous structures used for coastal protection.