• Water Engineering Research
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• v.2 no.2
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• pp.75-87
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• 2001

A new moving boundary technique for leap-frog finite difference numerical mode is proposed for the resonable simulation of coastal inundation over discontinuous topography. The new scheme improves the moving boundary technique developed by Imamura(1996). The present scheme is tested using the analytical solution of Thacker(1981) for the case of free oscillation with moving boundary in a parabolic bowl. Finally, a numerical simulation is conducted for the flooding over a tidal barrier constructed on a simple concave geometry. A general feature of inundation over a discontinuous topography is well described by the numerical model.

• Journal of Korea Water Resources Association
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• v.54 no.7
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• pp.463-474
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• 2021

The various external forces can cause inundation in coastal areas. This study is to analyze regional characteristics caused by single or compound external forces that can occur in coastal areas. Storm surge (tide level and wave overtopping) and rainfall were considered as the external forces in this study. The inundation analysis were applied to four coastal areas, located on the west and south coast in Republic of Korea. XP-SWMM was used to simulate rainfall-runoff phenomena and 2D ground surface inundation for watershed. A coupled model of ADCIRC and SWAN (ADCSWAN) was used to analyze tide level by storm surge and the FLOW-3D model was used to estimate wave overtopping. As a result of using a single external force, the inundation influence due to storm surge in most of the coastal areas was greater than rainfall. The results of using compound external forces were quite similar to those combined using one external force independently. However, a case of considering compound external forces sometimes created new inundation areas that didn't appear when considering only a single external force. The analysis considering compound external forces was required to reduce inundation damage in these areas.

• Journal of Ocean Engineering and Technology
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• v.22 no.3
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• pp.8-17
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• 2008

Wrenching climatic changes due to ecocide and global wanning are producing a natural disaster. Coastal zones have been damaged by typhoons and accompanying storm surges. Severe waves, and destruction of the environment are adding to the severity of coastal disasters. There has been an increased interest in these coastal zone problems, and associated social confusion, after the loss of life and terrible property damage caused by typhoon Maemi. Especially if storm surges coincide with high ticks, the loss of life and property damage due to high waters are even worse. Therefore, it is desirable to accurately forecast not only the timing of storm surges but also the amount water level increase. Such forecasts are very important from the view point of coastal defense. In this study, using a numerical model, storm surge was simulated to examine its fluctuation characteristics for the coastal area behind Masan Bay, Korea. In the numerical model, a moving boundary condition was incorporated to explain wave run-up. Numerically predicted inundation regimes and depths were compared with measurements from a field survey. Comparisons of the numerical results and measured data show a very good correlation. The numerical model adapted in this study is expected to be a useful tool for analysis of storm surges, and for predicting inundation regimes due to coastal flooding by severe water waves.

• Journal of Korea Multimedia Society
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• v.23 no.5
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• pp.710-720
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• 2020

Tsunami occurred by a rapid change in the ocean floor is a natural disaster that causes serious damage worldwide. South Korea seems to be out of the range of this damage, but it is quite possible that South Korea will fall within the range due to the long-distance propagation features of tsunami and many earthquakes occurred in Japan. However, the analysis and preparation for tsunami have been still insufficient. In this paper, we propose a tsunami simulation model based on cellular automata for analyzing coastal inundation. The proposed model calculates the range of inundation in coastal areas by propagating the energy of tsunami using the interaction between neighboring cells. We define interaction rules and algorithms for the energy transfer and propose a software tool to effectively utilize the model. In addition, to verify and tune the simulation model, we used the actual tsunami data in 2010 at Dichato, Chile. As a case study, the proposed model was applied to analyze the coastal inundation according to tsunami height in Gwangali Beach, a famous site in Busan. It is expected that the simulation model can be a help to prepare an effective countermeasure against tsunami and be used for a virtual evacuating training.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.2
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• pp.164-173
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• 2009

MIKE21, a commercial hydrodynamic model, was applied at the Masan Bay to evaluate the model's applicability of simulating the inundation phenomena. A storm surge/inundation model which adopts overflow computation scheme was applied together for comparison. The results of both models show correspondence with not only observed inundation area but also inundation water depth to prove their ability as inundation models. Especially, the accuracy of the MIKE21 model, which just adopts wetting/drying scheme, does not seem to be behind the inundation model. Moreover, an inundation simulation of the virtual MAEMI which was generated at preceding study, was conducted. The inundation area of the virtual MAEMI is similar to that of the real MAEMI, but inundation water depth is deeper than the real MAEMI.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.241-241
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• 2015

In this study, the simulations and analyses of flood flow due to a river inundation in a coastal urban area are carried out using a two-dimensional finite volume method with well-balanced HLLC scheme. The target area is a coastal urban area around Gohyun river which is located at Geoje city in Kyungnam province in Korea and was extremely damaged due to the heavy rainfall during the period of the typhoon "Maemi" in September 2003. For the purpose of the verification of the numerical model applied in this study, the simulated results are compared and analyzed with the inundation traces. Moreover, the flood flow in a urban area is simulated and analyzed based on the scenarios of inflow to the river with the increase and decrease of the intensity of the heavy rainfall.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.235-246
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• 2012

Typhoon induced surge simulations are done to make an establishment of coastal disaster prevention plan. To apply efficient run-up and overtopping on vertical harbor docks, in which prevailing wet-dry scheme cannot be satisfied due to infinite steepness, an imaginary internal barrier concept introduced and analyzed. Before real application on the Mokpo harbor area, feasibility tests are done on an idealized simple geometry and as a result it is found that the moderate width of the barrier might be 1 m. The threshold value of the minimum wet depth $H_{min}$ for land area, which behaves sensitive role in inundation area and depth, depends on grid size. However it is revealed that 0.01 m is adequate value in this fine finite element with 10 m spacing. A hypothetical typhoon of 100 years return period in central pressure and maximum velocity is generated based on historical tracks. Simulation of possible inundation on Mokpo area is performed with asymmetrical vortex of hypothetical typhoon and wave coupling. Model results show general agreement in pattern compared to other's prediction, however possibility of inundation enlargement is expected in harbor area.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.194-202
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• 2008

In general, forecast tsunami heights announced for tsunami warning are computed by using a linear tsunami model with coarse grids which leads the underestimation of inundation area. Thus, an accurate tsunami inundation map corresponding the forecast tsunami height is needed for an emergency evacuation plan. A practical way to construct a relatively accurate tsunami inundation map was proposed in this study for the quantitative forecast of inundation area. This procedure can be introduced as in the followings: The fault dislocations of potential tsunami sources generating a specific tsunami height near an interested area are found by using a linear tsunami model. Based on these fault dislocations, maximum inundation envelops of the interested area are computed and illustrated by using nonlinear inundation numerical model. In this study, the tsunami inundation map for Imwon area was constructed according to 11 potential tsunami sources, and the validity of this process was examined.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.270-278
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• 2010

Applicability of the MIKE21 model as a real time coupled tide-surge model had been examined at the previous study. In this study, another applicability of the model as an inundation model is also examined. Prior to real cases, effect of artificial structures on the inundation is analyzed. The results show that inundation depth is not altered, while inundation area is lessened as a result of decreased inundation speed. Comparative study between the coupled model and an uncoupled storm surge model is also carried out at the Masan coastal zone, which shows the coupled model is considered to be plausible at the time to maximum inundation, while both models show similar results at the inundation area and inundation depth.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.5
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• pp.287-294
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• 2010

In this study, a method to construct tsunami inundation map corresponding to the earthquake location and magnitude was proposed for tsunami real-time quantitative response. This proposed procedure can be introduced as in the followings: Potential tsunami source locations expected to cause damage in an interested area was identified. And numerical simulations were performed for various earthquake magnitudes. Based on numerical simulation results, inundation maps were constructed according to each source location and magnitude of tsunami generating earthquake. In this study, inundation maps for Imwon harbor were constructed for the 11 source locations and 7 earthquake magnitudes on a trial basis.