Influence of bilge-keel configuration on ship roll damping and roll response in waves

Jiang, Yichen; Ding, Ye; Sun, Yuan; Shao, Yanlin; Sun, Lei

doi:10.1016/j.oceaneng.2020.107539

Cited by 13 publications

(8 citation statements)

References 27 publications

(34 reference statements)

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“…The results of numerical simulations have shown that bilge keels can significantly increase the damping moment of a ship (Gu et al, 2015). The damping induced by the bilge keels depends not only on the area of the bilge keels but also on the distance from the vertical center of gravity, especially for ships with large breadth-to-draught ratios (Katayama et al, 2018;Jiang et al, 2020). The different effects of weight distribution on the damping coefficients for the ships with and without the bilge keels could be induced by the difference in the natural roll periods resulting from the different radii of gyration.…”

Section: Resultsmentioning

confidence: 99%

“…However, the damping moment induced by the bilge keels depends on the distance between the bilge keels and the ship's center of gravity in addition to the depth of the bilge keels from the water surface (Ikeda et al, 1978a;Ikeda et al, 1978b).The effect of distance between the bilge keels and the roll axis for a shallow draught ship with a large breadth-to-draught ratio has been verified by Katayama et al (2018). The increase of the equivalent damping moment was not commensurate with the increasing height of the bilge keels (Jiang et al, 2020). Fesman et al (2007) found that the use of bilge keels could reduce the roll angle of a ship by about 30%.…”

Section: Introductionmentioning

confidence: 98%

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Hydrodynamics Factors Correspond to the Weather Criterion Applied to an Indonesian Ro-Ro Ferry with Different Weight Distributions

Paroka¹,

Muhammad²,

Rahman³

2021

IJTech

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The effect of weight distribution on hydrodynamics factors in the weather criterion was investigated. Two types of weight distribution were examined. With the first type of distribution, the weight was concentrated near the centerline of the model. With the second, the weight was positioned farther from the centerline in order to obtain a natural roll period corresponding to that provided by the standard formula in the weather criterion of the International Maritime Organization (IMO). The three-step procedure recommended by the IMO was applied. A roll decay test and a roll test in a regular beam wave were conducted to obtain the natural roll period, the damping factors corresponding to the breadth-to-draught ratio and the bilge keels, and the effective wave slope coefficient. The damping factor corresponding to the breadth-to-draught ratio for the ship with a larger radius of gyration was larger than that for the ship with a smaller radius of gyration. The ship with a smaller radius of gyration had a larger damping factor due to bilge keels compared to the ship with a larger radius of gyration. The effective wave slope coefficient of the ship with the larger radius of gyration was larger than that for the ship with the smaller radius of gyration. The effect of bilge keels on the effective wave slope coefficient for the ship with a radius of gyration equal to that obtained by the weather criterion formula was not significant. The effect of weight distribution on the weather criterion was significant for the ship without bilge keels. A significant effect of bilge keels on the weather criterion occurred for the ship with a weight distribution corresponding to a radius of gyration coefficient closer to that obtained by the formula in the weather criterion.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Hydrodynamics Factors Correspond to the Weather Criterion Applied to an Indonesian Ro-Ro Ferry with Different Weight Distributions

Paroka¹,

Muhammad²,

Rahman³

2021

IJTech

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“…Generally, drag force may be neglected compared to inertia force for large floating bodies. Therefore, considering the above assumptions in the absence of current and neglecting the effect of hydrodynamic drag, the total hydrodynamic excitation 𝑀 𝐸 reduces to 𝑀 𝐸 (𝜃 ̈, 𝜃 ̇, 𝜏) = 𝑀 cos(𝛺𝜏), (6) where 𝑀 = 𝛻𝑔𝑘 𝑤 𝜁 𝑎 𝐺𝑀 ̅̅̅̅̅ (Bhattacharya [28]). 𝑘 𝑤 and 𝜁 𝑎 denote the wave number and wave amplitude, respectively.…”

Section: 𝐶(𝜃 ̇ 𝜃) = 𝐶 𝑒𝑞 𝜃 ̇ (4)mentioning

confidence: 99%

“…Results are obtained by numerical simulation followed by experimental validation. Jiang et al [6] investigated the influence of bilge-keel configuration on the two-dimensional roll decay of a typical Panamax ship model and roll response in waves. The free surface random-vortex method was applied with a new way of vortex generation to simulate free roll response and associated viscous flow field.…”

Section: Introductionmentioning

confidence: 99%

Controlling period-doubling route to chaos phenomena of roll oscillations of a biased ship in regular sea waves

Kumar

Mitra

2023

Preprint

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Dynamics, control, and stability of roll oscillations of a biased ship in regular sea waves are investigated. The ship under roll oscillation is modeled as the classical Helmholtz-Duffing oscillator with strongly nonlinear asymmetric restoring moment characteristics. The incremental harmonic balance (IHB) method, amended with a pseudo-arc-length continuation approach, is employed to obtain the uncontrolled and controlled frequency responses. The primary and subharmonic responses of the uncontrolled system are examined through the period-doubling route to chaos path. The same ship roll model is then investigated under state feedback control with time delay. In the control scheme, a moving weight is actuated by the delay controller to generate the anti-rolling moment. The stability of periodic responses is studied using the semi-discretization method with extended Floquet theory. Bifurcation points on periodic response branches are identified from the eigenvalue study. The effect of gains and time delay in the feedback loop in controlling the primary and subharmonic responses is investigated. Several chaotic responses obtained through period-doubling route to chaos paths are successfully controlled. Stable, periodic, and steady-state solutions obtained from the IHB method are verified by numerical integration (NI) of the equation of motion as and when applicable. Solutions are aided with phase portrait, Poincaré map, time history, and Fourier spectrum for better clarity. It is shown that appropriate selections of control parameters can effectively reduce the roll amplitude to a great extent with the improved measure of stability.

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“…Bilge keels, fin stabilizers, and rudder stabilizers are the widely accepted devices in this category. Bilge keels are simple [6]. Fin stabilizers and rudder stabilizers are both categorized as active damping devices, and fin stabilizers are the best active stabilizers at present.…”

Section: Introductionmentioning

confidence: 99%

Investigation of a Cabin Suspended and Articulated Rescue Vessel in Terms of Motion Reduction

Bai

et al. 2022

JMSE

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To solve the problem that small rescue vessels are seriously affected by waves when working at sea, which causes damage to the crew and equipment, a catamaran with a suspended and articulated cabin is designed. The multi-body dynamic model of the whole vessel based on SimMechanics is built, and the prototype is tested on the water. The correctness of the model is verified based on the three aspects of the roll motion, pitch motion, and heave motion of the rescue platform. The motion of the rescue platform is simulated under the conditions of bow waves and large heave waves, and the RMS value of the vertical acceleration of the rescue platform is taken as the response target to analyze the influence of the suspension system parameters of the whole vessel. The suspension system has good buffering and motion reduction effects under various working conditions, and it has an obvious reduction effect on the vertical acceleration at the rescue platform. The larger the amplitude of the wave impact, the more obvious the effect. The articulated system reduces the roll angle and the heave amplitude under the conditions of bow waves.

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Influence of bilge-keel configuration on ship roll damping and roll response in waves

Cited by 13 publications

References 27 publications

Hydrodynamics Factors Correspond to the Weather Criterion Applied to an Indonesian Ro-Ro Ferry with Different Weight Distributions

Hydrodynamics Factors Correspond to the Weather Criterion Applied to an Indonesian Ro-Ro Ferry with Different Weight Distributions

Controlling period-doubling route to chaos phenomena of roll oscillations of a biased ship in regular sea waves

Investigation of a Cabin Suspended and Articulated Rescue Vessel in Terms of Motion Reduction

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