A Study on Viscous Roll Damping of a Box-Shaped Vessel in the Frequency Domain Using the Discrete Vortex Method

2010 ◽  
Author(s):  
M Hajiarab ◽  
◽  
M Downie ◽  
M Graham ◽  
◽  
...  
Keyword(s):  
Frequency Domain ◽  
Vortex Method ◽  
Roll Damping ◽  
Discrete Vortex ◽  
Discrete Vortex Method

Prediction of Roll Damping in the Frequency Domain Using the Discrete Vortex Method

2010 ◽  
Author(s):  
Mohammad Hajiarab ◽  
J. Michael R. Graham ◽  
Martin Downie
Keyword(s):  
Frequency Domain ◽  
Model Test ◽  
Theoretical Approach ◽  
Three Dimensional ◽  
Separated Flow ◽  
Vortex Method ◽  
Roll Damping ◽  
Discrete Vortex ◽  
Discrete Vortex Method ◽  
Good Agreement

This paper describes a theoretical approach to predict roll damping for a three-dimensional barge shaped vessel in the frequency domain by matching a simple discrete vortex method (DVM), describing local separated flow, to an inviscid 3-D seakeeping code. The results are compared with model test experiments to demonstrate validity of the method. A good agreement between the model test RAO and the damped RAO is achieved.

A STUDY ON VISCOUS ROLL DAMPING OF A BOX-SHAPED VESSEL IN THE FREQUENCY DOMAIN USING THE DISCRETE VORTEX METHOD

2021 ◽  
Vol 153 (A2) ◽  
Author(s):  
M Hajiarab ◽  
M Downie ◽  
M Graham
Keyword(s):  
Frequency Domain ◽  
Model Test ◽  
Wave Amplitude ◽  
Vortex Method ◽  
Model Tests ◽  
Irregular Waves ◽  
Regular Waves ◽  
Roll Damping ◽  
Discrete Vortex ◽  
Discrete Vortex Method

This paper presents a study on viscous roll damping of a floating box-shaped vessel in the frequency domain. The application of the discrete vortex method (DVM) for calculation of the viscous roll damping in regular seas has been validated by model tests. Equivalent roll RAOs associated with a range of regular wave amplitudes are calculated to assess behaviour of the viscous roll damping in relation to incident wave amplitude linearisation. A model test is conducted using the model test facilities of the Marine Hydrodynamics Laboratory at Newcastle University to validate the applicability of the DVM in calculating the roll RAO in regular waves and to study the application of this method to irregular waves. Results of these model tests are presented in this paper.

Comparison of RANS Method and Discrete Vortex Method on Simulating the Roll Motion of a Ship With Bilge Keels

2018 ◽  
Author(s):  
Yichen Jiang ◽  
Xiaojie Zhao ◽  
Zhihua Zeng ◽  
Tiezhi Sun ◽  
Jiawen Li ◽  
...  
Keyword(s):  
Numerical Models ◽  
Vortex Method ◽  
Roll Motion ◽  
Fluid Viscosity ◽  
Roll Damping ◽  
Discrete Vortex ◽  
Discrete Vortex Method ◽  
Numerical Predictions ◽  
Bilge Keel ◽  
Rans Method

The prediction of roll motion of a ship section with bilge keels is particularly difficult because the flow separation and vortex shedding under the hull significantly affect the behavior of roll damping. To predict the roll damping and roll motion directly, the numerical models must simulate the fluid viscosity. Recently, Reynolds-averaged Navier–Stokes (RANS) method and Discrete Vortex Method (DVM) have been applied in this area and show promising results. In this paper, we will use both methods to simulate the free roll-decay motion of a ship section with bilge keels. The numerical predictions of the roll time histories will be compared with experimental measurements. Besides, the numerically-predicted vorticity distributions at different time instants near a bilge keel will be shown and compared. Moreover, the computation times for both numerical methods will also be reported. In this work, we will conduct the comparison for a number of cases that are with different bilge-keel heights and bilge-keel installation angles. Thus, the accuracies and the computational efficiencies will be evaluated comprehensively.

Note on governing equations for a discrete vortex method.

1986 ◽  
Vol 34 (391) ◽  
pp. 453-460
Author(s):  
Norio ARAI ◽  
Katsuhiko TAGUCHI
Keyword(s):  
Vortex Method ◽  
Governing Equations ◽  
Discrete Vortex ◽  
Discrete Vortex Method

Flows past a rotating circular cylinder by the discrete vortex method.

1989 ◽  
Vol 9 (34) ◽  
pp. 273-276
Author(s):  
Takeyoshi Kimura ◽  
Michihisa Tsutahara ◽  
Zhong-yi Wang ◽  
Hiroshi Ishii
Keyword(s):  
Circular Cylinder ◽  
Vortex Method ◽  
Discrete Vortex ◽  
Discrete Vortex Method ◽  
Rotating Circular Cylinder

A circle theorem technique to handle 2-D flows around arbitrary cylinders in discrete vortex method

2021 ◽  
Vol 209 ◽  
pp. 104496
Author(s):  
Guoqing Jin ◽  
Li Zou ◽  
Yichen Jiang ◽  
Zhi Zong ◽  
Zhe Sun
Keyword(s):  
Vortex Method ◽  
Discrete Vortex ◽  
Discrete Vortex Method ◽  
Circle Theorem

Discrete Vortex Method-Based Model for Ground-Effect Studies

AIAA Journal ◽  
2014 ◽  
Vol 52 (12) ◽  
pp. 2817-2828 ◽  
Author(s):  
Partha Mondal ◽  
N. Balakrishnan
Keyword(s):  
Ground Effect ◽  
Vortex Method ◽  
Discrete Vortex ◽  
Discrete Vortex Method
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