• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.1
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• pp.46-61
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• 2017

In the present work, the interaction analysis between tsunami bore and onshore bridge is approached by a numerical method, where the tsunami bore is generated by difference of upstream side and downstream side water levels. Numerical simulation in this paper was carried out by TWOPM-3D(three-dimensional one-field model for immiscible two-phase flows), which is based on Navier-Stokes solver. In order to verify the applicability of force acting on an onshore bridge, numerical results and experimental results were compared and analyzed. From this, we discussed the characteristics of horizontal force and vertical force(uplift force and downward force) changes including water level and velocity change due to the tsunami bore strength, water depth, onshore bridge form and number of girder. Furthermore, It was revealed that the entrained air in the fluid flow highly affected the vertical force.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.2
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• pp.92-108
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• 2017

Present work shows a numerical method to analysis of interaction analysis between solitary wave and onshore bridge. Numerical simulation is carried out by TWOPM-3D (three-dimensional one-field model for immiscible two-phase flows), which is based on Navier-Stokes solver. To do this, the solitary wave is generated numerically in numerical wave channel, and numerical results and experimental results were compared and analyzed in order to verify the applicability of force acting on an onshore bridge. From this, we discussed precisely the characteristics of horizontal and vertical forces (uplift and downward forces) changes including water level and velocity changes due to the variation of solitary wave height, water depth, onshore bridge's location and type, and number of girder. Furthermore, It is revealed that the maximum horizontal and vertical forces acting on the girder bridge show different varying properties according to the number of girder, although each maximum force acting on the girder bridge is proportional to the increasement of incident solitary wave height, and the entrained air in the fluid flow affects the vertical force highly.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.3
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• pp.161-169
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• 2020

Physical experiments have been performed in a wave basin to investigate change of the wave loading on the crown wall under obliquely incident wave conditions. The measurement was carried out with wave incidence angle of 0, 15, 30 and 45°. The pressure transducers were placed on the front and bottom face of the crown wall to obtain horizontal and uplift force as well. It was found that both the horizontal and vertical force decreases with the incidence angle. Based on the analysis of the experimental data, a formula was suggested to estimate the reduction rate of horizontal and vertical forces under obliquely incident waves.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.1-13
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• 2008

In the present work, wave transformation by vertical columns and its wave forces acting on them are discussed using a direct 3-D numerical model based on the VOF (Volume Of Fluid) method. The numerical results for wave transformations and wave forces are critically compared to an advanced experimental data, and provide the verification of the numerical model used in the present study. Overall model-data comparisons are good. After verification of the numerical model, it is used to simulate wave fields around dual vertical columns with arbitrary cross section, and the characteristics of nonlinear wave forces and wave transformations according to the variations of different cross section types of vertical columns, an interval of vertical columns and incident wave angle are discussed.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1998.09a
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• pp.100-105
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• 1998

해양구조물의 연직 원형파일에 작용하는 파력은 주로 항력과 관성력의 합으로 표시되는 Morison 식을 이용하여 결정하여 왔다. 그러나 Morison 식은 대칭형상을 유지하며 비교적 완만히 변화하는 파에 대해서 적용이 가능하다. 구조물 부재에 쇄파가 작용할 경우, 쇄파파력은 항력과 관성력에 추가하여 강한 충격쇄파력을 포함하게 된다. 본 연구는 임의 이차원 경사해빈에서 경계요소법을 적용하여 쇄파 내부점들의 수립자 속도 및 가속도를 계산하고, 이들을 이용하여 쇄파에 의한 쇄파파력을 계산하기 위한 모델기법을 수립한다.(중략)

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.4
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• pp.217-227
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• 2015

In this study, two-dimensional physical experiment was carried out to examine the applicability of the three formulas(Takahashi and Shimosako, 1994; Tabet-Aoul and Lambert, 2003; Li, 2007), which were proposed to calculate the wave forces acting on perforated caisson breakwaters. In order to quantitatively compare the measured with the estimated values based on the wave formulas, the refined index of agreement and the coefficient of determination were calculated, by which the degree of agreement was evaluated. Among the three wave formulas, DUT formula (Li, 2007) showed the smallest deviation from the measured forces, whereas Takahashi formula (Takahashi and Shimosako, 1994) showed the largest deviation. Meanwhile, comparison of the magnitude of the measured wave forces with those from the three formulas revealed that DUT formula slightly underestimate, while the others overestimate the measured forces.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.149-159
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• 2016

In this study, the solitary wave-induced tsunami force acting on an onshore bridges in coastal area was numerically modelled by means of TWOPM-3D based on Navier-Stokes solver and VOF method which can track free surface effectively. The validity of numerical analysis was verified by comparing the experimental tsunami bore force acting on vertical wall and column structure. In particular, the characteristics of tsunami force with the changing tsunami intensity were surveyed through numerical experiments. The availability of 3-dimensional numerical analysis was reviewed through the comparison between the existing numerical results and design criteria for each drag force coefficient by applying Morison equation considering only drag force. As reasonable and high-precision estimation method of tsunami force, it was suggested to apply the estimation method taking drag and inertial force into consideration at the same time.

• Journal of Korea Water Resources Association
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• v.47 no.11
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• pp.1067-1076
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• 2014

In this study, a series of hydraulic experiments are conducted to measure wave pressure on vertical structures with incident solitary waves that well represent characteristics of tsunamis. The pressure transducers measure time histories of wave pressure according to wave height to see pressure distribution. The force of incident solitary wave is estimated from integrated pressure distributions and represented with square and cylindrical columns. Experimental measurements are compared with the predictions of existing empirical formulas frequently used to design of coastal structures.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.401-412
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• 2008

Simulations of three-dimensional numerical wave tank are performed to investigate wave force acting on a large cylindrical structure and consequent wave deformation, which are induced by bore after breaking waves. The numerical model is based on the three-dimensional Navier-Stokes equations with a finite-difference method combined with a volume of fluid(VOF) method, which is capable of tracking the complex free surface, including wave breaking. In order to promote wave breaking of the incident wave, the approach slope was built seaward of the structure with a constant slope and a large cylindrical structure was installed on a flat bed. The incident waves were broken on the approach slope or flat bed by its wave height. In the present study, all waves acting on the large cylindrical structure were limited to breaking bore after wave breaking. The effects of the position of the structure and the incident wave height on the wave force and wave transformations were mainly investigated with the concern of wave breaking. Further, the relations between the variation of wave energy by wave propagation after wave breaking and wave force acting on the structure were discussed to give the understanding of the full-linear wave-structure interactions in three-dimensional wave fields.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.2
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• pp.100-108
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• 1998

Morison formula has been used in the determination of wave forces acting on vertical cylindrical piles of ocean structures. The formula, however, can be applied to mildly varying varying incident waves with symmetrical shapes. The breaking waves impinge on structures with very high impact forces, which completely differ from the inertia and drag forces of the Morison formula in both magnitudes and characteristics. In the present study, a boundary element method is applied to determine the water particle velocity and acceleration under the breaking waves. A numerical model is then developed to determine breaking wave forces utilizing those water particle kinematics. The results of the model is then developed to determine breaking wave forces utilizing those water particle kinematics. The results of the model agree well with existing experimental data, giving maximal wave forces 3 times and maximal moments 5 times larger than the Morison formula does.