Estimation of ship roll damping—A comparison of the decay and the harmonic excited roll motion technique for a post panamax container ship

2016 ◽  
Vol 120 ◽  
pp. 371-382 ◽  
Author(s):  
Sven Wassermann ◽  
Dag-Frederik Feder ◽  
Moustafa Abdel-Maksoud
Keyword(s):  
Roll Motion ◽  
Container Ship ◽  
Roll Damping ◽  
Ship Roll

scholarly journals Robust model predictive control employed to the container ship roll motion using fin-stabilizer

2016 ◽  
Vol 3 (1) ◽  
pp. 1235478
Author(s):  
Hamid Malekizade ◽  
Mohammad Reza Jahed-Motlagh ◽  
Bijan Moaveni ◽  
Ali Moarefianpour ◽  
Hassan Ghassemi
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Roll Motion ◽  
Container Ship ◽  
Robust Model Predictive Control ◽  
Robust Model ◽  
Ship Roll ◽  
Fin Stabilizer ◽  
Ship Roll Motion

A Piecewise Model for Prediction of Large Amplitude Total Ship Roll Damping

2011 ◽  
Author(s):  
Christopher C. Bassler ◽  
Arthur M. Reed ◽  
Alan J. Brown
Keyword(s):  
Large Amplitude ◽  
Roll Motion ◽  
Practical Implementation ◽  
Roll Damping ◽  
Damping Characteristics ◽  
Ship Roll ◽  
Piecewise Model ◽  
Physical Changes ◽  
Physical Phenomena ◽  
Bilge Keel

A piecewise model is presented to model total ship roll damping, with considerations for large amplitude roll motion effects, such as bilge keel interaction with the free-surface. The model is based on the consideration of distinct ship-specific physical phenomena, such as bilge keel emergence. Abrupt physical changes occur with these events, resulting in significant changes in the damping characteristics of the system. Without these considerations, roll motion may be under-predicted. Some additional considerations needed for the practical implementation of the proposed piecewise model are also discussed.

Roll Decay Model Test of a Post Panamax Container Ship: Experimental and Numerical Analysis

2013 ◽  
Author(s):  
Henry Piehl ◽  
Ould el Moctar
Keyword(s):  
Ship Hull ◽  
Roll Angle ◽  
Body Motion ◽  
Roll Motion ◽  
Numerical Comparison ◽  
Container Ship ◽  
Roll Damping ◽  
Joint Research ◽  
Decay Test ◽  
Joint Research Project

The slender shape of a modern ship hull, exhibits a roll motion that is — in contrast to heave and pitch motion — submitted to large amplitudes and weak damping. This effect explains the importance of determining the roll damping of a hull and denotes the difficulty to measure such a small dynamic property. For the joint research project Best-Roll a series of roll decay tests were conducted with the model of a post panamax container ship. To capture the influence of the draft and the ship velocity, the roll motion was measured for a systematic variation of these parameter. In addition the tests were performed with an initial roll angle of 20 degrees, in order to investigate the nonlinear damping behavior at large roll angles. The objective of the subsequent study was to test the capability of OpenFOAM to compute the overall roll damping of a ship hull and appendages. For the numerical comparison, the roll decay test was simulated with OpenFOAM, using a transient multiphase solver with a RANS turbulence model, dynamic mesh motion and a rigid body motion model of the ship. The results were compared by calculating the roll damping coefficient for both experiment and numerical simulation by means of time series analysis of the roll angle.

scholarly journals Ship roll motion prediction based on ℓ1 regularized extreme learning machine

PLoS ONE ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. e0206476 ◽  
Author(s):  
Binglei Guan ◽  
Wei Yang ◽  
Zhibin Wang ◽  
Yinggan Tang
Keyword(s):  
Extreme Learning Machine ◽  
Motion Prediction ◽  
Roll Motion ◽  
Ship Roll ◽  
Learning Machine ◽  
Ship Roll Motion

Ship Roll Motion Damping Using Bilge Keels – A Detailed CFD Investigation

2015 ◽  
Author(s):  
Joshua Counsil ◽  
Kevin McTaggart ◽  
Dominic Groulx ◽  
Kiari Boulama
Keyword(s):  
Experimental Studies ◽  
The Body ◽  
Navier Stokes ◽  
Roll Motion ◽  
Empirical Methods ◽  
Viscous Effects ◽  
Vortex Interactions ◽  
Ship Roll ◽  
Semi Empirical ◽  
Bilge Keel

A study has been undertaken to test the value of unsteady Reynolds-averaged Navier-Stokes (URANS) and traditional semi-empirical methods in the face of complex ship roll phenomena, and provide insight into the selection of bilge keel span for varying roll amplitudes. The computational fluid dynamics (CFD) code STAR-CCM+ is employed and two-dimensional submerged bodies undergoing forced roll motion are analyzed. The spatial resolution and timestepping scheme are validated by comparison with published numerical and experimental studies. The model is then applied to a fully-submerged circular cylinder with bilge keels of varying span and undergoing roll motion at varying angular amplitudes. Extracted hydrodynamic coefficients indicate that in general, increasing displacement amplitude and bilge keel span yields increased added mass and increased damping. The relationship is complex and highly dependent upon vortex interactions with each other and the body. The semi-empirical methods used for comparison yield good predictions for simple vortex interactions but fail where viscous effects are strong. Hence, URANS methods are shown to be necessary for friction-dominated flows while semi-empirical methods remain useful for initial design considerations.

Nonlinear Roll Damping and Roll Motion Study of Asymmetric Catamaran With Variable Layouts

2020 ◽  
Author(s):  
Yihan Zhang ◽  
Jingfeng Hu
Keyword(s):  
Numerical Methods ◽  
Great Influence ◽  
Prediction Method ◽  
Potential Method ◽  
Roll Motion ◽  
Roll Damping ◽  
Overlapping Grids ◽  
Motion Study ◽  
Seakeeping Performance ◽  
Ship Speed

Abstract Because of the interference between the main hull and side hull, the layout of asymmetric catamaran has a great influence on the seakeeping performance. In order to assess the characteristics of roll damping and roll motion of this kind of ship, firstly, a numerical prediction method of roll damping is established by CFD with overlapping grids to simulate the roll decay curves at different transverse and longitudinal spacing and ship speed. The roll damping property is analyzed by energy method and flow field monitoring. Then, based on the correction of nonlinear roll damping, the roll motion response in waves is calculated by 3D potential method. Finally, model tests are carried out to verify the numerical methods. The change of transverse layout has a great influence on the roll damping and roll motion of the asymmetric catamaran, while the longitudinal layout has a little influence on the roll performance. The research results of this paper can provide some useful reference for the design of asymmetric catamaran.

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