• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.581-589
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• 2019

In order to understand the characteristics of beach deformation, in this study, numerical simulations were conducted using a 3-D hydro-morphodynamic model (HYMO-WASS-3D) to analyze the characteristics of beach deformation due to the coastal groundwater levels. HYMO-WASS-3D directly analyzed the nonlinear interaction between the hydrodynamic and morphodynamic processes in the coastal area. The simulation results of HYMO-WASS-3D showed good agreement with the experimental results on the changes in the profile of the beach in the surf and swash zones. Then, numerical simulations were conducted to examine the characteristics of beach deformation due to the variation of the level of the coastal groundwater. As a result, the beach profiles were examined in relation to the wave breaking in the surf zone and the wave uprush and backwash in the swash zone due to the differences in the water levels. This paper also discussed the temporal and spatial distributions of the velocities, vorticities, and suspended sediments in the surf and swash zones with various levels of the coastal groundwater.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.4
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• pp.645-650
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• 2016

In this study, we conducted a numerical simulation using Navier-Stokes Solver (HYMO-WASS-3D) in order to analyze wave attenuation under wave-current interaction found in existing hydraulic experiments. It showed that wave energy and wave height are reduced as the wave propagates in coexisting fields between waves and currents. And the wave attenuation became more serious as the velocity of current and thus turbulence intensity were increased at wave-current coexisting field. As well, the wave attenuation became more serious with lower wave height and shorter period when the wave propagates the same distance under interactions between waves and currents.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.831-838
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• 2016

The disaster preventing system using vegetation has been growing in the field of coastal engineering in recent years. To analyze wave and flow fields under nonlinear interactions between tsunami and vegetation, the purpose of this study is to evaluate newly-developed 3-D numerical wave tank including energy dissipation by tsunami-vegetation interaction based on existing N-S solver with porous body model. Comparing numerical results using mean drag coefficient and dynamic drag coefficient due to Reynolds number to existing experimental results it is revealed that computed results considering the dynamic drag coefficient are in good agreement with the laboratory test results for time-domain waveform. In addition, the calculated transmission coefficients of solitary waves in various vegetation densities and incident wave heights are also in good agreement with the experimental values. This confirms the validity and effectiveness of the developed 3-D numerical wave tank with the fluid resistance by vegetation.