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.

Multiple Ship Motion Simulation Code Correlation with Model Test Results

2017 ◽  
Author(s):  
James A. Coller ◽  
Andrew Silver ◽  
Okey Nwogu ◽  
Benjamin S.H. Connell
Keyword(s):  
Real Time ◽  
Model Test ◽  
Three Dimensional ◽  
Angle Measurement ◽  
Ship Motion ◽  
Ship Motions ◽  
Simulation Code ◽  
Forecasting System ◽  
Scale Experiment ◽  
Response Amplitude Operators

The US Nav has developed a real-time multi-ship ship motion forecasting system which combines forecast wave conditions with ship motion simulations to produce a prediction of the relative motions between two ships operating in a skin-to-skin configuration. The system utilizes two different simulation methods for predicting ship motions: MotionSim and Reduced Order Model (ROM) based on AEGIR. MotionSim is a fast three-dimensional panel method that is used to estimate the Response Amplitude Operators (RAOs) necessary for multi-ship motion predictions. The ROM works to maximize the accuracy of high fidelity ship motion prediction methods while maintaining the computational speed required for real-time forecasting. A model scale experiment was performed in 2015 on two Navy ships conventionally moored together. The predicted relative ship motions from MotionSim and ROM were compared to the model data using three different metrics: RMS (root mean square) ratio, correlation coefficient, and average angle measurement (AAM).This paper provides an overview of the two methods for predicting the multi-ship motions, a description of the model test, challenges faced during testing, and a discussion on the methodology of the evaluation and the results of each code correlation.

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.

Experimental Study on a Relation Between Nonlinear Hydrodynamic Forces and Wave-Induced Ship Motions

2019 ◽  
Author(s):  
Masakazu Taguchi ◽  
Masashi Kashiwagi
Keyword(s):  
Large Amplitude ◽  
Equations Of Motion ◽  
Linear Equations ◽  
Hydrodynamic Forces ◽  
Ship Motion ◽  
Ship Motions ◽  
Practical Calculation ◽  
Wave Loads ◽  
Nonlinear Ship Motion ◽  
Wave Induced

Abstract Nowadays, in maritime industries, container ships increase in size and they have large flares, which may induce nonlinear wave loads in large-amplitude waves. It is also well known that hydrodynamic forces acting on a ship and resulting ship motions show nonlinearities at some range of wave frequencies. Therefore, we should investigate not only correct estimation of wave loads and ship motions, but also nonlinear ship-motion characteristics in large-amplitude waves. However, it is not that clear which nonlinear hydrodynamic force terms are dominating for the nonlinearity in the ship motions. Although the linear equations of motion have been used, they should be modified to incorporate at least the most important nonlinear hydrodynamic forces and to establish a practical calculation method taking account of only the indispensable nonlinear terms. In this research, we did extensive experimental measurement of hydrodynamic forces and wave-induced ship motions, with which we aim to understand what are practically important nonlinear terms, and to derive practical nonlinear ship motion equations through numerical computation and comparison with experimental data.

Development of Design Technologies for Optimum Moonpool Shapes of Drill Ship

2007 ◽  
Author(s):  
Jong Jin Park ◽  
Mun Sung Kim ◽  
Hee Sung Lee ◽  
Young Kyu Ahn ◽  
Young Bok Kim ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Free Surface ◽  
Input Data ◽  
Three Dimensional ◽  
Ship Motions ◽  
Surface Movement ◽  
Seakeeping Analysis ◽  
Simulation Results ◽  
Six Degree Of Freedom ◽  
Rough Sea

The present study is concerned with the numerical and experimental analysis of a moonpool in rough sea. From hydrodynamic viewpoint, a moonpool of drill ships can cause various problems. Among them, two major problems arise such as an increased resistance and overflow on the deck due to pumping up phenomena. To overcome these inherit problems, we have carried out various numerical analysis to find optimum moonpool shapes. The three-dimensional numerical model adopting SOLA-VOF scheme is used to predict violent free surface movement inside of a moonpool due to irregular ship motions with six degree of freedom. For accurate input data of ship motions, a three dimensional panel method program is applied for seakeeping analysis. The resistance and seakeeping model test have been carried out at MARINE to validate the proposed moonpool shapes, which have been designed based on numerical simulation results.

Motion Prediction of the Ship With Sloshing Tanks

2009 ◽  
Author(s):  
Kang Zou ◽  
Quan-ming Miao ◽  
Ren-qing Zhu
Keyword(s):  
Time Domain ◽  
Three Dimensional ◽  
Panel Method ◽  
Ship Motion ◽  
Motion Prediction ◽  
Ship Motions ◽  
Motion Responses ◽  
Motion Problem ◽  
Good Agreement

Sloshing flow in ship tanks is excited by ship motions, but it affects the ship motions in reverse. This paper focuses on the motion responses of the ship in waves with consideration of coupled effects with sloshing in tanks. A three-dimensional panel method in time-domain is applied to solve the ship motion problem, and the sloshing tanks are solved by commercial CFD software simultaneously. Experiments were carried out on a SL175 ship and good agreement is obtained.

Numerical Simulation of Maneuvering of "Naniwa-maru," A Full-scale Reconstruction of Sailing Trader of Japanese Heritage

2003 ◽  
Author(s):  
Yutaka Masuyama ◽  
Kensaku Nomoto ◽  
Akira Sakurai
Keyword(s):  
Numerical Simulation ◽  
Equations Of Motion ◽  
Time History ◽  
Ship Motions ◽  
Measured Time ◽  
Generic Class ◽  
History Of ◽  
Heading Angle ◽  
Ship Performance ◽  
Rudder Angle

Numerical simulation of maneuvering of “Naniwa-maru" was performed to clarify the maneuver characteristics in particular with wearing operation. "Naniwa-maru" belongs to a type called Higaki-kaisen, and the Higaki-kaisen is a type of the more generic class of vessels named "Bezai-ship". Bezai-ship are typical Japanese sailing traders in the 18th to the mid- 19th century which have different appearance and construction from those of Western tall ships. The present paper shows the numerical simulation of her wearing operation, and the results compared with the measured data. The equations of motion dealt with coupled ship motions of surge, sway, roll and yaw with co-ordinate system using horizontal body axes. The numerical simulation indicates ship response according to the measured time history of rudder angle, and shows the ship trajectory and the sailing state parameters such as heading angle, leeway angle, heel angle and velocity. The calculated results indicated the ship performance very well.

Numerical Simulation of Ship Maneuvering in Pack Ice

2010 ◽  
Author(s):  
Dexin Zhan ◽  
Daniel Agar ◽  
Moqin He ◽  
Don Spencer ◽  
David Molyneux
Keyword(s):  
Numerical Simulation ◽  
Numerical Modeling ◽  
Discrete Element Method ◽  
Computer Program ◽  
Open Water ◽  
Discrete Element ◽  
Mathematical Methods ◽  
Ship Maneuvering ◽  
Pack Ice ◽  
Ice Loads

This paper presents preliminary results from a computer program for simulating ship maneuvering in ice covered waters. The program is derived from two programs, Ship Maneuvering Laboratory (SML) and a discrete element numerical modeling program (DECICE). SML is an in-house code developed by Oceanic Consulting Corporation for simulating ship maneuvering in open water. It is based on a ship maneuvering model originally developed by the Japanese mathematical maneuvering group (MMG). DECICE is a discrete element method which was developed by INTERA Technologies and is used to calculate the ice loads on the ship and the interactions between ice pieces. The paper presents a summary of the mathematical methods used together with the results of some case studies for ships EXM004, PSM004 and Esso Osaka Tanker. These computer predictions include turning circle and Zig-Zag maneuvers. Comparisons and discussion of the simulated results between cases with and without ice are also provided.

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

Design and calibration of an IVEM for general 3-dimensional imaging of non-diffracting materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1040-1041
Author(s):  
Neil Rowlands ◽  
Jeff Price ◽  
Michael Kersker ◽  
Seichi Suzuki ◽  
Steve Young ◽  
...  
Keyword(s):  
3D Imaging ◽  
Tomographic Reconstruction ◽  
Three Dimensional ◽  
3 Dimensional ◽  
3D Microstructure ◽  
Image Translation ◽  
Digital Correlation ◽  
On Line ◽  
Mechanical Stage ◽  
Projection Angle

Three-dimensional (3D) microstructure visualization on the electron microscope requires that the sample be tilted to different positions to collect a series of projections. This tilting should be performed rapidly for on-line stereo viewing and precisely for off-line tomographic reconstruction. Usually a projection series is collected using mechanical stage tilt alone. The stereo pairs must be viewed off-line and the 60 to 120 tomographic projections must be aligned with fiduciary markers or digital correlation methods. The delay in viewing stereo pairs and the alignment problems in tomographic reconstruction could be eliminated or improved by tilting the beam if such tilt could be accomplished without image translation.A microscope capable of beam tilt with simultaneous image shift to eliminate tilt-induced translation has been investigated for 3D imaging of thick (1 μm) biologic specimens. By tilting the beam above and through the specimen and bringing it back below the specimen, a brightfield image with a projection angle corresponding to the beam tilt angle can be recorded (Fig. 1a).

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