On the Effect of Water on Deck on Ship Motion

2002 ◽  
Author(s):  
Dimitris Spanos ◽  
Apostolos Papanikolaou ◽  
George Tzabiras
Keyword(s):  
Numerical Simulation ◽  
Satisfactory Agreement ◽  
Simulation Method ◽  
Interaction Force ◽  
Ship Motion ◽  
Simplified Model ◽  
Ship Motions ◽  
Efficient Simulation ◽  
Water On Deck ◽  
Present Simulation

The effect of trapped water on deck or the interior compartments of ships on ship motions is closely investigated by use of a non-linear numerical simulation method. The employed method enables the efficient simulation of the wave excited, coupled ship – trapped water motions and proves to be a very valuable tool for the assessment of the survivability of flooded ships in waves. A detailed study has been carried out to more carefully investigate the coupling effects between the ship and the floodwater mass that can be expressed through a resultant interaction force. This interaction force has been approximated both by a simplified model employed by the present simulation method and also by a more accurate CFD code and satisfactory agreement between the results of both approaches has been obtained.

Dynamic Behavior of Moored Ship Motions Induced by Initial Attack of Large Scaled Tsunami

2005 ◽  
Author(s):  
Shigeki Sakakibara ◽  
Masayoshi Kubo ◽  
Eiichi Kobayashi ◽  
Shunichi Koshimura
Keyword(s):  
Numerical Simulation ◽  
Tsunami Wave ◽  
Simulation Method ◽  
Ship Motions ◽  
Initial Attack ◽  
Simulation Procedure ◽  
Drag Forces ◽  
Large Ship ◽  
Selection Of ◽  
Safe Working

In this paper, we propose a numerical simulation procedure of moored ship motions due to initial attack of large scaled tsunamis and investigate the effects on the motions and mooring loads. The effect of methodology on selection of tsunami wave components and of the drag forces are then considered by using the numerical simulation method, applying to several case studies for LNG-carrier. Large ship motions and excessive mooring loads beyond the safe working loads are induced by the resonant tsunami wave components in the sway and surge motions, and drag forces.

Numerical Simulation of Ship Motions in Regular and Irregular Waves

2019 ◽  
Vol 53 (1) ◽  
pp. 97-106
Author(s):  
Bao-Ji Zhang ◽  
Jie Liu ◽  
Ning Xu ◽  
Lei Niu ◽  
Wen-Xuan She
Keyword(s):  
Numerical Simulation ◽  
Wave Length ◽  
Simulation Method ◽  
Irregular Waves ◽  
Navier Stokes ◽  
Ship Motions ◽  
Vof Model ◽  
Split Operator ◽  
Strip Theory ◽  
Cfd Method

AbstractA numerical simulation method is presented in this study to predict ship resistance and motion responses in regular and irregular waves. The unsteady RANS (Reynolds Average Navier-Stokes) method is selected as the governing equation, and a volume of fluid (VoF) model is used to capture the free surface, combining the k-ε equations. A finite volume method (FVM) is utilized to discretize both the RANS equations and VoF transport equation. The pressure implicit split operator (PISO) method is set as the velocity-pressure coupling equation. The overset mesh technique is utilized to simulate ship motions in waves. A DTMB5415 ship is selected as a case study to predict its pitch and heave responses in regular and irregular waves at different wave length and wave steepness. The ship is free to move in the pitch and heave directions. The CFD (Computational Fluid Dynamics) results are found to be in good agreement with the strip theory and experimental data. It can be found that the CFD method presented in this study can provide a theoretical basis and technical support for green design and manufacture of ships.

scholarly journals Study on environmental impact of artificial horizontal freezing method in subway connecting passage

2020 ◽  
Vol 198 ◽  
pp. 04023
Author(s):  
Changyi Yu ◽  
Mingyue Lu
Keyword(s):  
Numerical Simulation ◽  
Environmental Impact ◽  
Simulation Method ◽  
Simplified Model ◽  
Thermophysical Parameters ◽  
Freezing Method ◽  
Geological Conditions ◽  
Complex Boundary ◽  
Artificial Freezing ◽  
Artificial Freezing Method

When the subway is built in complex urban strata, especially when excavating near buildings, it is necessary to strictly control the freezing amount by adopting artificial freezing method. At present, the theoretical calculation is aimed at the frozen rise under ideal conditions, but for complex geological conditions, the simplified model results are difficult to meet the actual requirements. However, numerical calculation can adapt to complex strata and complex boundary conditions. Therefore, in this paper, the environmental impact of artificial horizontal freezing method in subway connecting passage is studied by numerical simulation, and the change of thermophysical parameters with the change of temperature field is considered in the simulation. The simulation method in this paper provides guidance for actual construction.

scholarly journals A SLACK MOORING FOR A LARGE SHIP UNDER BEAM SEAS IN PORT

2018 ◽  
pp. 57
Author(s):  
Shigeki Sakakibara ◽  
Shunji Sunahara ◽  
Kaku Ito
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Mooring Line ◽  
Ship Motions ◽  
Physical Model Test ◽  
Mooring Lines ◽  
Beam Seas ◽  
Large Ship ◽  
Small Ship ◽  
Slack Mooring

As an empirical and traditional ship mooring method, a pretension mooring (a hard mooring) or slack mooring (without pretension in mooring line) is performed for large ship or small ship, respectively. However, the slack mooring is applied to a large ship under beam seas in port to avoid large roll and sway motions, and excessive loads in mooring lines and fenders. In this study, the mechanism and validity of the slack mooring for large ship is investigated by a physical model test and a numerical simulation method of the moored ship motions and mooring loads under beam seas.

3-Dimensional Numerical Simulation of Ship Motion in Pack Ice

2012 ◽  
Author(s):  
Dexin Zhan ◽  
David Molyneux
Keyword(s):  
Numerical Simulation ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Ship Motion ◽  
Ship Motions ◽  
Discrete Element Modeling ◽  
Ship Maneuvering ◽  
3 Dimensional ◽  
Pack Ice ◽  
Ice Concentration

In OMAE2010, the authors presented a two dimensional numerical simulation for predicting ship maneuvering in pack ice. This paper is an expansion of this analysis to include a three dimensional numerical simulation for an arctic drill ship moving in pack ice (with ice concentration up to 90%) using a discrete element modeling program (DECICE3D) combined with a ship maneuvering code (SML). The mathematical models of ship motion, ice motion and ship-ice interaction are introduced in the paper. Ship motions of steady drift angle, turning about a turret, turning circle and zigzag maneuvers in pack ice are simulated. The results of the simulations are compared with experimental data or results of simulations for ice free conditions. A sensitive study for the effects of the mass damping term used in the equations of motion is conducted.

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