• Journal of Ocean Engineering and Technology
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• v.12 no.3 s.29
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• pp.75-85
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• 1998

A finite difference model for predicting time-dependent, wave-induced nearshore current is studied. The model includes wave refraction, wave-current interaction, bottom friction and wind effect. This model iteratively solved the linear the linear set of conservation of both mass and momentum, which were time averaged (over one wave period) and depth integrated, for mean velocities and free surface displacement. Numerical simulations of nearshore current under oblique wave attack, and for wave and wind induced current on a longshore periodic beach are carried out. Longshore velocities tend to zero in some distances outside the breaker line. And the peak velocity is shifted shoreward at the breaker line. The results represent the general characteristics of the nearshore current induced by wave.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.2
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• pp.185-193
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• 2010

In the present study, wave deformation and wave-induced current were calculated under the regular wave conditions using the Boussinesq model. The model results of the wave deformation showed good agreements with the preceeding laboratory experiments of others. The wave-induced current of the fully developed sea state was calculated. For field application of model, the preceeding field data by others in the real scale of the water area were compared, the numerical result of wave deformation showed a relatively good agreement with the field data. Although the numerical result of wave-induced current was underestimated over the longshore bar developed area, the Boussinesq model is generally suitable to predict the wave-induced current.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.155-166
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• 1999

The construction of the coastal structures and reclamation work causes the circulation reduced in the semi-closed inner water area and the unbalanced sediment budget of beach results in an alteration of beach topography. Among the various fluid motions in the nearshore zone water particle motion due to wave and wave-induced currents are the most responsible for sediment movement. Therefore it is needed to predict the effect of the environmental change because of development and so the prediction of wave transformation dose. The purpose of this study is to introduce the relation between waves wave-induced currents and sediment movement. In this study we will show numerical method using energy conservation equation involving reflection diffraction and reflection and the surfzone energy dissipation term due to wave breaking is included in the basic equation. For the wave-induced current the momentum equation was combined with radiation stresses lateral mixing and friction Various information is required in the prediction of wave-induced current depending on the prediction tool. We can predict changes in wave-induced current from the distribution of wave especially near the wave breaking zone. To evaluate these quantities we have to know the local condition of waves mean sea level and so on. The results from the wave field and wave-induced current field deformation models are used as input data of the sediment transport and bottom change model. Numerical model were established by a finite difference method then were applied to the development plan of the eastern Pusan coastal zone Yeonhwa-ri and Daebyun fishing port. We represented the result with 2-D graphics and made comparison between before and after development.

• Journal of Korean Port Research
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• v.12 no.2
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• pp.269-280
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• 1998

A Wave-induced current model is developed in our study and this model is composed with wave transform model and current model. Two types of wave model are used in our study one is Copeland(1985) type which is applied in the offshore region and the other is Watanabe and Maruyama(1984) type which is applied in the surf zone. The depth-integrated and time-averaged governing equation of an unsteady nonlinear form is used in the wave induced current model. Lateral mixing radiation stresses surface and bottom stresses are considered in our current model. Copeland’s(1976) is used as a surface friction formula. Numerical solutions are obtained by Leendertse scheme and compared with Noda’s(1974) experimental results for the uniform slope coastal region test and Nishimura & Naruyama’s (1985) experimental results and numerical simulation results for the detached breakwater. The results from our wave model and wave model and wave-induced current model show good agreements with the others and also show nonlinear effects around the detached breakwater. The model in this study can be applied in the surf zone considering the friction stresses.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10a
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• pp.189-199
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• 1998

Wave-induced current model is developed in our study and this model is composed with wave transform model and current model. Two types of wave model are used in our study, one is Copeland(1985) type which is applied in the offshore region and the other is Watanabe and Maruyama(1984) type which is applied in the surf zone. The depth-integrated and time-averaged governing equation of an unsteady nonlinear form is used in the wave induced current model. Lateral mising, radiation stresses, surface and bottom stresses are considered in our current model. Copeland's(1985) relult is used to calculate radiation stress and Berkmeir & Darlymple's(1976) is used as a surface friction formula. Numerical solutions are obtained by Leendertse scheme and compared with Noda's(1974) experimental results for the uniform slope coastal region test and Nishimura & Maruyama's(1985) experimental relults and numerical simulation results for the detached breakwater test. The results from our wave model show good agreement with the others and also show nonlinear effects around the detached breakwater. Wave induced current model is developed in this study and this model shows nonlinear effects around the detached breakwater and can be applied in the surf zone and also consider the friction stresses.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.6
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• pp.565-573
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• 2007

The effect of wave and current interactions on irregular wave transformation over a submerged elliptic shoal is investigated based on numerical simulations of the Vincent and Briggs experiment [Vincent, C.L., Briggs, M.J., 1989. Refraction-diffraction of irregular waves over a mound. Journal of Waterway, Port, Coastal and Ocean Engineering, 115(2), pp. 269-284]. The numerical simulations are conducted by a combination of REF/DIF S(a wave model) and SHORECIRC(a current model) and a time dependent phase-resolving wavecurrent model, FUNWAVE. In the simulations, the breaking-induced currents defocus waves behind the shoal and bring on a wave shadow zone that shows relatively low wave height distributions. The computed results of the combined model system agree better with the measurements than the computed results obtained by neglecting wave-current interaction do. In addition, the results of FUNWAVE show a good agreement with the measurements. The agreement indicates that it is necessary to take into account the effect of breaking-induced current on wave refraction when wave-breaking occurs over a submerged shoal.

• 한국해양학회지
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• v.15 no.1
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• pp.1-7
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• 1980

The results of measurements of shear current induced in water by wind in wind wave tunnel are presented briefly. The shear current distributions are found to fit reasonably well an exponentiall form. This form was used to estimate surface velocity and boundary layer thickness used in stability analysis. An analysis of hydrodynamic stability of the shear current was carried out, using a broken line as an approximate profile, to see the stability as a possible mechanism of wind wave generation. Comparison between experimental results and theoretical ones shows that there exists a large discrepancy particularly in phase velocity and hydrodynamic instability of the shear current seems not to be the basic mechanism of wind wave generation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.142-149
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• 2019

In this study, the past erosion history and current status in the CHUNG-UI beach of Eulwang-dong, Jung-gu, Incheon-Si, South Korea were investigated and analyzed the wave with wave-induced current to investigate the causes of coastal erosion. As a result, the significant wave height ($H_{1/3}$) was in the range of 0.07~1.57 m and the mean value was 0.21 m. The maximum wave height ($H_{max}$) was in the range of 0.02-4.76m and the mean value was 0.27m. The vertical wave height and cycles were estimated through numerical model experiments of wave transformation. The 50-year frequency design wave height ranged from 0.82m to 3.75m. As a result of the experiment of wave-induced current, wave-induced current in the CHUNG-UI beach was decreased after the installation of the Detached breakwater and the Jetty. On the other hand, when the crest elevation was increased up to 5 m, there was no significant change, but when the crest elevation was increased to 8m, strong wave-induced current occurred around the submerged breakwaters due to lowered depth of water. In addition, the main erosion of the CHUNG-UI beach is due to the intensive invasion of the wave characteristics coming from the outer sea into the white sandy beach. The deformation of the wave centered on the front of the sandy beach caused additional longshore currents flowing parallel to the sandy beach and rip currents in the transverse direction, thus confirming that the longshore sediment was moved out of the front and out of the sea. The results of this study can be used as preliminary data for the recovery of the sand and the selection of efficient erosion prevention facilities.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.2
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• pp.136-145
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• 2007

When waves propagating over an underwater shoal break at the top of the shoal, wave heights are drastically decreased in the downstream breaking zone, but a secondary current shooting downstream with strong velocity can be induced by the breaking waves themselves. In the case that an offshore structure is placed in the breaking zone, the estimation of wave farce purely based on the visible wave height may cause an under-design of the structure. Thus, for the safe design of the structure, the breaking wave induced current should be necessarily considered in the comprehensive estimation of design load. In the present study, Boussinesq equation model to calculate the wave height distribution and breaking wave induced current was set up and applied to the scheme of a hydraulic model test previously undertaken. Based on the results of the Boussinesq model, fluid forces acting on the model structure were calculated and compared with the experimental results. The importance of the breaking wave induced current was quantitatively assessed by comparing fluid forces with or without current.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.3
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• pp.202-212
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• 2005

In the design of an of offshore structure located near an underwater shoal, the same amount of attention given to the wave height may have to be put to the wave induced current as well since some of the wave energy translates to the current. In the present study, two numerical models each based on the nonlinear Boussinesq equation and the linear mild slope equation are applied to calculate the wave deformation and secondly induced current around a shoal. The underwater shoal in Vincent and briggs' experiment (1989) is used here, and all non-breaking wave conditions of the experiment with various monochromatic and unidirectional or multidirectional spectral wave incidences are concerned. Both numerical models clearly showed wave induced currents symmetrically farmed along the centerline over the shoal. The calculated wave heights along a preset line also generally showed very nice agreements with the experimental values.