• 한국해양공학회지
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• 제20권3호
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• pp.24-36
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• 2006

This paper investigates wave loads of ships that suffer sinkage due to flood in a compartment caused by damage on the side of the hull. By analyzing ships with various sizesof damage opening, the influence of opening size on ship response is investigated. The motion of the damaged ship is analyzed by using the boundary element method, based on three-dimensional potential theory, considering hydrodynamic pressure in the flooded compartments. The shear forces, bending moments and torsional moments are calculated by the direct integration of the three dimensional hydrodynamic pressure on the outer and inner hulls. A RORO passenger ship with length of 174.8 m is considered in the numerical example, and results for wave loads are discussed.

• 대한조선학회논문집
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• 제42권4호
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• pp.379-387
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• 2005

A ship may suffer sinkage and heel due to flood in a compartment caused by damage on a deck. The motion and waveloads of the heeled ship floating in waves have been analyzed by making use of a three dimensional potential theory taking account of the hydrodynamic pressure in the flooded compartments. The shear forces and bending moments due to radiation-diffraction waves have been calculated by the direct integration of the 3-d hydrodynamic pressure on the outer and inner hulls of floating barges. The motion responses and the relative flow rate across the mean free surface of the water in the flooded compartments are also presented.

• 한국해양공학회지
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• 제33권1호
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• pp.1-9
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• 2019

This paper considers a numerical assessment of the self-propulsion performance of a damaged ferry carrying cars in irregular waves. Computational fluid dynamics(CFD) simulations were performed to see whether the ferry complied with the Safe Return to Port (SRtP) regulations of Lloyd's register, which require that damaged passenger ships should be able to return to port with a speed of 6 knots (3.09 m/s) in Beaufort 8 sea conditions. Two situations were considered for the damaged conditions, i.e., 1) the portside propeller was blocked but the engine room was not flooded and 2) the portside propeller was blocked and one engine room was flooded. The self-propulsion results for the car ferry in intact condition and in the damaged conditions were assessed as follows. First, we validated that the portside propeller was blocked in calm water based on the available experimental results provided by KRISO. The active thrust of starboard propeller with the portside propeller blocked was calculated in Beaufort 8 sea conditions, and the results were compared with the experimental results provided by MARIN, and there was reasonable agreement. The thrust provided by the propeller and the brake horsepower (BHP) with one engine room flooded were compared with the values when the engine room was not flooded. The numerical results were compared with the maximum thrust of the propeller and the maximum brake horse power of the engine to determine whether the damaged car ferry could attain a speed of 6 knots(3.09 m/s).

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2018년도 추계학술대회
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• pp.248-255
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• 2018

Deep-sea fishing vessel No. 501 Oryong was fully flooded through the openings and was sunk down to the bottom of sea due to the very rough sea weather on the way of evasion after fishing operation in the Bearing Sea with many crews dead and/or missed. In this study, calculation of ship stability was carried out using KST-SHIP(ship calculation system of KST), considering the effect of flow fluid and fish catch arrangement according to the progress of its sinking accident, and damage stability was analyzed. For this study, intact stability calculation of its accident ship under the full load departure condition and its calculation result were verified by comparing with each other, and intact stability according to displacement from the departure of accident ship just before the accident was calculated and analyzed. Damage stability was calculated according to the progress during sinking accident and also analyzed.

• 대한조선학회논문집
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• 제43권4호
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• pp.451-459
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• 2006

When a ship is damaged and flooded, the motion of the damaged ship is significantly influenced by the flooding water dynamics. The flooding water in the damaged ship has been treated as a lumped mass under the quasi-static assumption in most of previous researches. To calculate the motion of damaged ship rigorously, it is necessary to analyze the coupled dynamics of flooding water. In this study, a series of numerical and experimental studies is conducted for the damaged part of ITTC RORO passenger. FLOW3D is used for investigating the feasibility of the state of the art CFD technique. An applicability of the coupled motion analysis of damaged ships can be confirmed by agreement between the numerical results and the model experiments. A CFD technique is considered for the numerical modeling of the dynamics of flooding water.

• 한국해양공학회지
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• 제38권3호
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• pp.124-136
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• 2024

As the number of offshore wind-power installations increases, collision accidents with vessels occur more frequently. This study investigates the risk of collision damage with operating vessels that may occur during the operation of an offshore wind turbine. The floater used in the collision study is a 15 MW UMaine VolturnUS-S (semi-submersible type), and the colliding ships are selected as multi-purpose vessels, service operation vessels, or anchor-handling tug ships based on their operational purpose. Collision analysis is performed using ABAQUS and substantiation is performed via a drop impact test. The collision analyses are conducted by varying the ship velocity, displacement, collision angle, and ship shape. By applying this numerical model, the extent of damage and deformation of the collision area is confirmed. The analysis results show that a vessel with a bulbous bow can cause flooding, depending on the collision conditions. For damage caused by collision, various collision angles must be considered based on the internal stiffener arrangement. Additionally, the floater can be flooded with relatively small collision energy when the colliding vessel has a bulbous bow.

• 대한조선학회논문집
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• 제49권2호
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• pp.164-173
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• 2012

Landing ship tank with well dock has the important mission transferring troops or landing equipments from sea to shore. Such transfers are usually carried out using landing crafts, which are loaded or unloaded in flooded well dock. In this situation, as relative motions are occur between well dock and landing craft, safety verifications are demanded. In this paper, seakeeping and safety performances are investigated through model test. First of all, well dock dimensions are reviewed and model tests are performed with sea state 3&4 in 180degree wave direction. Model tests are conducted for three relative positions and seakeeping performances are investigated each position.

• 대한조선학회논문집
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• 제49권1호
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• pp.52-59
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• 2012

Among many factors to be considered for higher safety level requirements, the hull stability in intact and damaged conditions in seaways is of utmost importance. Since the assessment of a damaged ship is complicated due to the highly non-linear behavior, it is widely acknowledged that computational fluid dynamics (CFD) methods are one of the most feasible approaches. Although many research activities are being reported on the damaged ship stability recently, most of them are not designed for validation of CFD studies. In this study, well-designed model tests were performed to build a CFD validation database, which is essential in developing better CFD methods for the damage stability assessment. The geometry of the damaged compartment and test conditions were determined based on preliminary CFD simulations. Free roll decay tests in calm water with both intact and damaged ships were performed and the roll motion characteristics were compared. The damaged ship showed a larger roll damping coefficient and more rapid decrease of roll amplitude than the intact ship. The primary reason of these efforts can be explained by the movement of the flooded water.

• 한국항해항만학회지
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• 제42권6호
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• pp.459-468
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• 2018

원양어선 제501 오룡호는 황천 중인 베링해에서 조업 후 피항하던 중 개구부를 통한 침수로 인하여 침몰하였으며 많은 선원들이 사망하고 실종되었다. 본 연구에서는 사고선박 침몰사고의 진행상황 별 유동수 영향과 어획물 배치 등을 고려한 선박복원성 계산을 KST-SHIP (선박안전기술공단 선박계산시스템)을 사용하여 수행하고 사고선박의 침몰사고 시의 침수 후 선박복원성을 분석하였다. 먼저 만재출항상태 (Full Load Departure Condition)에서의 사고선박의 비손상 복원성 계산서와 KST-SHIP을 사용한 비손상 선박복원성 계산 결과를 비교하여 검증하고, 사고선박의 출항 시부터 사고 직전까지의 배수량에 따른 비손상 복원성 계산을 수행하여 비손상 복원성을 분석하였다. 또한 사고선박 침몰사고 시의 진행상황 별 침수 후 선박복원성 계산을 수행하여 침수 후 복원성도 분석하였다.

• 한국CDE학회논문집
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• 제21권1호
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• pp.90-98
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• 2016

When ships and offshore plants are flooded or the floating crane is equipped with a heavy object, these floating structures are excessively inclined. In this case, immersion, heel, and trim affecting the hydrostatic restoration performance are very large and are coupled each other. In this paper, in order to calculate a static equilibrium position of floating structures with excessive inclination, the nonlinear governing equations were constructed by sequential linearization. In the governing equation, the immersion, heel, and trim are fully coupled, and the equations are represented using a plane area, a primary moment, and a moment of inertia of the water plane area. Therefore, it is possible to calculate the additional factor related the water plane area for estimating stability. Position and orientation of the floating structure are obtained by iterative calculation. The calculated results are compared with the previous studies in the aspect to the performance and the accuracy.