The joint and normal probability distributions of alpha and gamma for extreme and normal waves showed a Gaussian distribution, allowing identification of specific alpha and gamma values for the JONSWAP spectra model. Furthermore, the standardized effects of alpha and gamma over the Tp during extreme wave states suggest quadruplets of wave-wave interactions. The DOE-ANOVA demonstrated for the mean and extreme wave states of the study area that alpha and gamma parameters positively affect the Hs behavior in deep and intermediate waters. The present study performed a design of experiment (DOE)-analysis of variance (ANOVA) and probability analysis to assess the effect of alpha and gamma parameters over the significant wave height (Hs) and peak period (Tp) during sea-state and water-depth transitions. Therefore, the model coefficient selection should be tested using a nonlinear analysis to assess the effect of the selected spectra coefficients over the modeled wave parameters. Proper selection of the model coefficients (e.g., alpha and gamma of the JONSWAP spectra) is then required, because of the wave-hydrodynamic nonlinearities during these ocean processes. The design of marine structures requires the simulation of wave parameters that consider sea-state and water-depth transitions. The findings made in this paper enhance the understandings on the damage mechanisms of coastal bridges under the impact of extreme waves. submersion depth, wave height, wave period, and water depth. The NWT was then used to study the hydrodynamic loads of a coastal bridge deck by considering the effects of four prominent factors, i.e. The NWT was validated for the case of focused waves and wave impact loads on a two-dimensional (2D) rectangular cylinder in a straight channel and compared to experimental measurements. Simulations were carried out by creating a numerical wave tank (NWT) using the open-source flow solver REEF3D, which numerically solves the governing equations of the incompressible two-phase flow on a staggered mesh and captures the interface between air and water using a high-resolution level-set method. This work adds to the existing body of work by systematically carrying out numerical investigations on the hydrodynamic characteristics of coastal bridge decks under the impact of extreme waves generated by wave focusing. Although impacts of various types of waves on coastal bridges had been studied in the past, hydrodynamic loads on bridge deck under the impact of extreme waves had not yet been investigated. Coastal structures such as bridges are highly susceptible to extreme waves and have caused substantial damage to coastal infrastructure in the past. Extreme waves often are attributed to the process of wave focusing. It is hoped that the research findings drawn from this study can further broaden our understanding on the wave attenuation of extreme waves by coastal vegetations.Įxtreme waves, such as freak waves or rogue waves, occur unexpectedly in the ocean and have extremely large wave heights. The results indicate that the emergent rigid vegetation patch can effectively reduce the maximum wave amplitude of focused wave by averagely 31% and the total wave energy by averagely 45%, thus, showing that coastal vegetation can effectively protect the coast from extreme waves. The efficiencies of the rigid emergent vegetation patch in mitigating the maximum wave amplitude and total wave energy of both crest and trough focused waves as function significant wave height, peak wave period, water depth, vegetation density and width have been well analyzed and discussed. To numerically evaluate the wave attenuation of extreme waves by the emergent rigid vegetation patch, a high-resolution numerical wave tank has been established by applying the nonhydrostatic numerical wave model (NHWAVE), where both 2nd-order crest and trough focused waves can be generated by considering wave-wave interactions. Usually, focused wave is used as a typical extreme wave model to study the great impact of extreme waves on the coast. Field observations after extreme weather events have revealed that as a type of natural barrier, coastal vegetations can effectively attenuate the intensity of extreme surges and waves and thus play a good role in naturally protecting the coast. Attributed to the processes of wave focusing, extreme waves often occur unexpectedly with huge wave height in both deep and shallow water regions, which can cause serious damages to the coastal infrastructures, and threaten the intactness of coastal communities.
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