Interactive forces and moments between several ships meeting in confined waters

Varyani, K.S.; McGregor, R. C.; Wold, P.

doi:10.1016/s0967-0661(98)00056-2

Cited by 15 publications

(7 citation statements)

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“…Fang and Kim (1986) utilized a 2D procedure, including the hydrodynamic interaction and an integral equation method, to predict the coupled motions between two ships advancing in oblique seas. Varyani et al (1998Varyani et al ( , 2002 also used a 2D method to calculate the interaction forces acting on two or more ships meeting in restricted waters.…”

Section: Introductionmentioning

confidence: 99%

Ship-to-Ship Interaction During Overtaking Operation in Shallow Water

Yuan¹,

He²,

Kellett³

et al. 2015

Journal of Ship Research

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Hydrodynamic interaction continues to be a major contributory factor in marine casualties and hazardous incidents, in particular in the case of overtaking operations. The situation becomes even worse when the overtaking operation occurs in shallow and narrow channels where the interaction can cause the vessels to collide and, in one case has caused the capsizal of the smaller vessel with loss of life. The aim of this paper is to propose a methodology, as well as to discuss the development of a numerical program, to predict the ship-to-ship interaction during overtaking operations in shallow water.Since the vessels involved in the present study have different forward speeds, an uncoupled method will be used to solve the boundary value problem. The in-house multi-body hydrodynamic interaction program MHydro, which is based on the 3D Rankine source method, will be used and extended here to investigate the interactive forces and wave patterns between two ships during an overtaking operation.The present calculations are compared with model test results as well as published CFD calculations.Very satisfactory agreement has been obtained, which indicates that the proposed methodology and developed program are successfully validated to predict the hydrodynamic interaction between two ships advancing in confined waters. The discussions also highlight the speed effects.

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Section: Introductionmentioning

confidence: 99%

Ship-to-Ship Interaction During Overtaking Operation in Shallow Water

Yuan¹,

He²,

Kellett³

et al. 2015

Journal of Ship Research

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“…Among them, X i , Y i and N i are obtained through a large number of ship wind tunnel tests [22]. In this paper, the formulas of wave forces and moment are:…”

Section: Mathematical Model Of Pod Driven Ship Dynamic Positioninmentioning

confidence: 99%

Adaptive Backstepping Sliding Mode Dynamic Positioning System for Pod Driven Unmanned Surface Vessel Based on Cerebellar Model Articulation Controller

2020

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The dynamic positioning system is a system that ships rely on their own propulsion devices to maintain position and course. Pod propulsion was more and more installed in dynamic positioning unmanned surface vessels because it can rotate 360 degrees freely. The maximum disturbance of unmanned surface vessel dynamic positioning comes from the forces and moments generated by the ocean wind, wave and current. In order to improve its accuracy of disturbance rejection, the mathematical model of the vessel was established according to the special structure of pod propulsion ship, and the calculations of the forces and moments of wind, wave and current are given. Then, the sliding mode controller based on approach law and adaptive backstepping were designed, and optimal controller based on cerebellar model articulation controller (CMAC) was further designed. The tracking differentiator was added to eliminate the large chattering in the initial stage of the system. Finally, the simulation verification was carried out. It can be seen from the results that the control law designed has better control effects than traditional sliding mode control and can realize dynamic positioning of pod driven unmanned surface vessel under certain disturbances. INDEX TERMS Cerebellar model articulation controller, dynamic positioning system, pod propulsion, sliding mode control, unmanned surface vessel.

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“…where x is the distance between the two ships during the attempted overtaking manoeuvre and B is the breadth of a vessel of a given class. This simplified approach neglects all the hydrodynamic effects that occur when two ships are moving on parallel courses in very close proximity [45][46][47][48]. Therefore, the distance between two ships on parallel courses that causes a collision may be greater than the adopted value.…”

Section: Overtaking and Head-on Situationsmentioning

confidence: 99%

Marine traffic risk modelling – an innovative approach and a case study

Montewka

Krata

Goerlandt

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part O:

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This paper presents a model to analyse the risk of two common marine accidents: collision and grounding. Attention is focused on oil tankers since they pose the highest environmental risks. A case study in selected areas of the Gulf of Finland in ice-free conditions is presented. The model utilizes a formula for risk calculation that considers both the probability of an unwanted event and its consequences. The model can be decomposed into a block representation in which blocks for the probability of a collision, probability of a grounding event, and the consequences of an accident are linked. The probability of vessel colliding is assessed in terms of a minimum-distance-to-collision-based model. The model defines the collision zone using a mathematical ship motion model and considers the traffic flow to be a non-homogeneous process. Calculations are performed using data for traffic flows in the Gulf of Finland with particular attention being paid to the crossing of the channel used by scheduled ferries between Helsinki and Tallinn, and the main shipping channel. For the assessment of a grounding probability, a new approach is proposed, which utilizes a gravitylike model, where a ship and navigational obstructions are perceived as interacting objects and their repulsion is modelled by a formulation inspired by gravitational force. The considered situation in this case is the movement of oil tankers in the approach channel to an oil terminal at Sköldvik, near Helsinki. The consequences of an accident are expressed in monetary terms, and concern the costs of cleaning up an oil spill, based on the statistics of compensation levels claimed from the International Oil Pollution Compensation Fund.

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Interactive forces and moments between several ships meeting in confined waters

Cited by 15 publications

References 0 publications

Ship-to-Ship Interaction During Overtaking Operation in Shallow Water

Ship-to-Ship Interaction During Overtaking Operation in Shallow Water

Adaptive Backstepping Sliding Mode Dynamic Positioning System for Pod Driven Unmanned Surface Vessel Based on Cerebellar Model Articulation Controller

Marine traffic risk modelling – an innovative approach and a case study

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