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MANOEUVRING OF HIGH-SPEED SHIPS Mr.E. ARMAOGLU SSRC, Dept of Naval Architecture & Marine Engineering, Universities of Glasgow and Strathclyde, UK Presentation Outline • • • • • Introduction - Aims Types of Instabilities of HSC Current Mathematical Model The Path to be Followed Current Research Progress Introduction Manoeuvring of High Speed Craft from Stability and Safety Point of View WATCH OUT FOR COLLISIONS!!! Prevention (IMO 1997): • Sufficient Controllability • Adequate Dynamic Stability • Sufficient Manoeuvrability Introduction Recommendation From The 22nd ITTC Specialist Committee of High Speed Marine Vehicles Problems relating to High-Speed roll, pitch and directional stability anomalies must be solved with accompanying model tests to find the effect of Position of Centre of Gravity and GM on course-stability and capsize. Types of Instabilities of HSC INSTABILITIES DEFINED BY ITTC and more… • Pure Loss of Stability (Loss of GM due to wave system) • Course Keeping (e.g. Broaching, Parametric Rolling) • Bow-Diving • Chine-Tripping • Spray-Rail Engulfing • Porpoising • Additionally Chine-walking and Corkscrew Current Mathematical Model Manoeuvring Mathematical Model by Dr. Ayaz Features: • 6 Degrees of Freedom • Frequency Dependent Coefficients • Incorporating Memory Effects • No Restrictions on Motion Amplitudes • Axis System That Allows Combination of Seakeeping and Manoeuvring Models Mathematical Model System of Coordinates Mathematical Model Mathematical Model Equations of Motion ω V ) X m (V G G F ω H X H G G M Where m is the mass of a ship, HG the momentum about the centre of gravity, the angular velocity, VG the linear velocity and XF, XM the external force and moment vectors, respectively. Mathematical Model Equations of Motion VR) X' m( U UR) Y' m( V mW Z' mg 1 K` (I yy I xx )[sin2 θ (QP R) cos 2θ QR] 2 I RQ (I xx cos 2 θ I yysin 2 θ) P yy 1 2 R )] 2 (I xx cos 2 θ sin 2 θ)RP I yy Q M` (I yy I xx )[sin2 θ ( 1 N' (I xx I zz )[sin 2θ (QR P) cos 2θ QP] 2 (I xx sin 2 θ I zz cos 2 θ)R Mathematical Model Equations of Motion X : ζ a , ξ G , x, y, z, u, v, w, p, q, r, φ, θ, ψ, δ T denotes rudder or pod angle, g and a represent horizontal and vertical component of wave amplitude B (X) X C (X)X F(ζ , X, X ,X ) (M A)X w where, M is inertia Matrix, A is added inertia matrix, B is damping coefficient matrix, C is restoring coefficient matrix, F is external force vector and w is wave amplitude. Mathematical Model External Forces X' X W X H X RS X RD X P Y' YW YH YRD YP Z' Z W Z H K' K W K H K RD K P M' M W M H N' N W N H N RD N P W indicates wave forces and moments, H indicates hull (manoeuvring) forces and moments and radiation forces and moments for vertical motions, RS indicates resistance forces, RD indicates rudder forces and moments and P indicates propeller forces and moments Mathematical Model External Forces [Automatic Control] The standard proportional-differential (PD) autopilot is employed in this model δ R t r δ R k1 (ψ ψ R ) k 2 ψ R is the actual rudder angle, R is the desired heading angle, k1 is yaw angle gain constant, k2 is yaw rate gain constant and tr is the time constant in rudder activation The Effect of the New Mathematical Model on Motion The Effect of the New Mathematical Model on Motion The Path to be Followed • Steady Manoeuvring Motion Effect of Running Attitude on Manoeuvring Hydrodynamic Forces at High Speed • Unsteady Manoeuvring Motion Memory Effects • Oscillatory Instabilities Effect of Vertical Lift Force on Stability Motion • Non-Oscillatory Instabilities Effect of Vertical Lift Force on Manoeuvring Hydrodynamic Forces An Oscillatory Type Instability for a High-Speed Craft: Coupling Between Horizontal and Vertical Motions Experiment Video from Osaka Prefecture University is Presented with Permission of Dr. Toru Katayama The Challenge HAVING A MATHEMATICAL MODEL TO ACCOUNT FOR ALL THESE PROBLEMS IN EXTREME RANDOM WAVES FOR HIGH-SPEED CRAFTS The Current Research Progress Investigation of the behavior of high-speed craft at irregular seas based on this mathematical model is progressing. Further steps include the addition of vertical lift component and coupling effects between vertical and horizontal motions to our mathematical model. Questions? THANK YOU FOR LISTENING