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1、Shanghai Jiao Tong University2nd Semester,Academic Year2014-2015Summary of Ship Manoeuvrabilityfor ReviewProf. Dr.-Ing. Zou ZaojianMay 14, 2015Slide 2 Summary of Ship ManoeuvrabilityOutline Introduction Evaluation and Prediction of Ship Manoeuvrability Equations of Ship ManoeuvringMotion Dynamic Sta
2、bility of Ships Initial Turning and Turning Ability of Ships Control Devices Measures to Improve Ship Manoeuvrability Some Remarks on the ExaminationSlide 3Introduction Purpose of the courseto answer the questions： What is “ship manoeuvrability” (What does “ship manoeuvrability” deal with) ? Whyshou
3、ld a ship have good manoeuvrability? Howto evaluate ship manoeuvrability(How to make judgementif a ship has good or poor manoeuvrability) ? How to ensure that a ship is designed/built with good manoeuvrability(If a ship has poor manoeuvrability, or the manoeuvrabilityis not good enough, how to take
4、measures to improve its manoeuvrability) ?Summary of Ship ManoeuvrabilitySlide 4Introduction (continued) Ship Manoeuvrabilityand Its ContentsManoeuvrability: The abilityof a ship to keep orchange its state of motionunder control actions according to the intention of the helmsman.Ship manoeuvrability
5、includes : (definition) Inherent dynamic stability (straight line stability) Course-keeping ability (directional stability) Initial turning/course-changing ability Yaw-checking ability Turning ability Stopping abilitySummary of Ship ManoeuvrabilitySlide 5Introduction (continued) Importance of Ship M
6、anoeuvrabilityNavigation safety(examples)Navigation economy(examples) Factors which affect navigation safety（1）Ship manoeuvrabilityitself（2）Human factors (most important !)（3）Environmental factors (wind, waves, current; restricted waters; etc.) Closed-loop Control System for Ship ManoeuvringShip Hel
7、msman (Pilot or autopilot) Control Devices Environmental effects ShipSummary of Ship ManoeuvrabilitySlide 6Evaluation of Ship Manoeuvrability Standard manoeuvresand theparameters for evaluating ship manoeuvrabilityHow to conduct these manoeuvres? The parameters obtained from these manoeuvres?How can
8、 these parameters be used to evaluate shipmanoeuvrability? Turning test Zig-zagtest Stopping test (crash stop test) Spiral test (direct spiral and reverse spiral test) Pull-out testSummary of Ship ManoeuvrabilitySlide 7 IMO Standards for Ship ManoeuvrabilityTurning ability (with turning test)Initial
9、 turning ability (withzig-zagtest)Yaw-checking and course-keeping abilities (withzig-zagtest) Stopping ability (with stopping test) Full-scale Trial Conduct the standard manoeuvreswith full-scale ship to obtain the parameters for evaluating ship manoeuvrabilitySummary of Ship ManoeuvrabilityEvaluati
10、on of Ship Manoeuvrability(continued)Slide 8Prediction of Ship Manoeuvrability The methods which can be used for predicting ship manoeuvrabilityat the ship design stage: (1) Empirical method (database, empirical formulae for theparameters for evaluating ship manoeuvrability)(2)Free-running model tes
11、ts(by conducting the standardmanoeuvreswith ship model)(3) Mathematical models(Equations of ship manoeuvringmotion) +computer simulation (simulation of the standard manoeuvres)(4) Direct numerical simulation of the standard manoeuvresby using CFD (Computational Fluid Dynamics) techniquesThe second o
12、ne and the third one are the most commonly used methods for predicting ship manoeuvrabilityat the ship design stage.Summary of Ship ManoeuvrabilitySlide 9Equations of Ship ManoeuvringMotion Mathematical models (Equations of ship manoeuvringmotion)Coordinate systems(1) earth-fixed coordinate system(2
13、) body-fixed coordinate system with the origin lying on the center of gravity of the ship(3) body-fixed coordinate system with the originlying on the midshipsectionHow to derive the equations of ship manoeuvringmotion in these coordinate systems?Summary of Ship ManoeuvrabilitySlide 10Equations of Sh
14、ip ManoeuvringMotion(continued) Expressions of the hydrodynamic forces in the equations of ship manoeuvringmotionAbkowitzmodel(MIT professor, whole-ship model)(1) The hydrodynamic force (and moment) actingon hull-propeller-rudder system as a whole (2) The hydrodynamic force (and moment) expressedby
15、Taylor expansion, with the steady forwardmotion state as the expansion pointMMG model(Japanese mathematical modellinggroup, modular model) The hydrodynamic force (and moment) are divided into three parts: on hull, on propeller and on rudder,with the hydrodynamic interactions among them being taken i
16、nto account.Summary of Ship ManoeuvrabilitySlide 11 Methods for determining the hydrodynamic forces acting on a manoeuvringship（1）Captive model tests (How are these tests conducted?)Oblique-towing testRudder force testRotating-arm testPMM test (pure sway, pure yaw tests, etc.) Circular Motion Test（2）Semi-empirical method (database, empirical formulae, etc.)（3）System identificati
