Krzysztof Patalong. Master Thesis

Transcription

1 STANDARD MANOEUVRES SIMULATION OF A FISHING VESSEL Master Thesis developed at "Dunărea de Jos" University, Galaţi in the framework of the EMSHIP Erasmus Mundus Master Course in Integrated Advanced Ship Design Ref BE-ERA MUNDUS-EMMC Supervisor: Prof. Dr. Ing. Dan Obreja Reviewer: Prof. Dr. Ing. Marco Ferrando Galați/Nantes February 2012

2 MAIN GOALS OF THE THESIS Investigation of Validation of the Analysis of the accuracy and reliability university-developed CFD techniques of existing simulation code application in initial design programs for detailed design manoeuvring prediction (TRIBON, MPP1) (PHP code) (ShipFLOW) 2

3 MILESTONES OF THE THESIS 1. Design of the rudder geometry 2. Estimation of the hydrodynamic forces and moments generated on the rudder determination of the position and diameter of the rudder stock preliminary checking of the rudder cavitation 3. Estimation of the manoeuvring performance by means of the preliminary methods (based on regression formulas and linear hydrodynamic models) using simulation code based on fully non-linear hydrodynamic model 4. CFD simulationof forcesand momentson the hulland rudder itselfatdifferentdrift and rudder deflection angles 3

4 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 4

5 MATHEMATICAL MODELS General form of differential equations of motions system (horizontal plane): u 2 X = m rv r xg t v dr Y = m + ru + xg t dt r v N = I zz mx G ru t + t + Linear equations of motion (1 st order terms only): X + X u + X u& = mu& e u u& ( ) ( ) Y + Y v + Y r + Y v& + Y r& = m v& + ru + rx & e v r v& r& G N + N v + N r + N v& + N r& = I r& + mx v& + ru e v r v& r& zz G Non-linear model for ship s manoeuvrability (Abkowitz, 1964, Chislett and Strom-Tejsen, 1965): ( m X u& ) u& = X uu + X e + f1 ( u, v, r, δ ) ( m Yv& ) v& + ( mxg Yr& ) r& = Yvv + ( Yr mu ) r + Ye + f2 ( u, v, r, δ ) ( mx N ) v& + ( I N ) r& = N v + ( N mx U ) r + N + f ( u v r δ ) G v& zz r& v r G e 3,,, 5

6 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 6

7 Manoeuvring Prediction Methods: Data-bases of manoeuvring qualities Experimental model tests Mathematical models and numerical simulations STANDARD MANOEUVRES OF THE SHIP Standard Manoeuvres: Turning Circle Manoeuvre turning ability and efficiency of the rudder Zig-Zag Manoeuvre initial response to rudder action Spiral Manoeuvre controls-fixed straight line stability 7

8 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 8

9 IMO CRITERIA FOR STANDARD MANOEUVRES 9

10 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 10

11 GENERAL CHARACTERISTICS OF THE FISHING VESSEL Length overall, L OA [m] 32.7 Draft at fore perpendicular, T F [m] 2.42 Length between perpendiculars, L [m] 25.0 Draft at aft perpendicular, T A [m] 2.74 Moulded breadth, B [m] 8.0 Block coefficient, C B Volumetric displacement, [m 3 ] Stock propeller diameter, D [m] 1.8 Medium draft, T M [m] 2.58 Ship speed, U [kn] 12.0 Complicated hullform: double hard chine inclined (false) keel + Operation: at fairly high Fn 0.4 in trimmed condition 11

12 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 12

13 bt / c RUDDER DESIGN AND HYDRODYNAMIC PERFORMANCE DNV recommend. for min. A R : A = + = L T L 2 2 B CB Typical values of aspect ratio: TYPE OF SHIP Aspect ratio Coaster ships Ships with Tugs 1.8 single screw Fishing vessels span [m] b 2.20 chord [m] c 1.31 area [m 2 ] A R 2.88 max. thickness [m] t max 0.24 aspect ratio [-] λ 1.68 relative thickness [-] t / c BRIX METHOD Flow angle, α [deg] Static pressure [kpa] Dynamic pressure [kpa] Total pressure [kpa] all +ve = no cavitation risk Hydrodynamic characteristics Optimal distance from the the rudder stock to the leading edge [m] Optimal distance from the the rudder stock to trailing edge [m] VOITKOUNSKY METHOD Value Total hydrodynamic torque [knm]

14 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 14

15 VERIFICATION OF RESISTANCE ESTIMATION METHODS Holtrop & Mennen method (accuracy claimed to be satisfactory for 95% of the cases) for trawlers, coasters, tugs: Fn C P L/B B/T 3.0 Van Oortmerssen method small ships such as trawlers or tugs: 10 Fn C P L/B B/T L WL 80.0 Fishing vessel s parameters Fn = 0.39 C P = L/B = 3.1 B/T = 3.1 L WL = 26.7 m Resistance comparison Propeller revolutions comparison Resistance [kn] Speed [kn] Holtrop & Mennen Van Oortmerssen Experimental Fluid Dynamics Propeller revolutions [rpm] Speed [kn] 8

16 MANOEUVRABILITY PERFORMANCE IN THE INITIAL DESIGN STAGE Characteristics Numerical result IMO max. value Advance [non-dim.] Tactical diameter [non-dim.] Condition Stable Characteristics Numerical result IMO max. value 1 st overshoot angle [deg] nd overshoot angle [deg]

17 TRIBON: LIMITS OF APPLICABILITY AND COMPARISON WITH MPP1 Limits of applicability of TRIBON: resistance estimation with BSRA method in Manoeuvring Module (Methodical Series Experiments on Single-Screw Ocean-Going Merchant-Ship Forms with 0.55 < C B < 0.85) conventional rudders only in Manoeuvring Module (conventional, Becker or Schilling rudder types in other modules) based on mathematical models derived from regression analysis of manoeuvr. characteristics of merchant and naval vsls SHIP Min. value: Max. value: Fishing vsl OK? Block coefficient (C B ) YES Beam/Draft (B/T) YES Length/Beam (L/B) NO Length/Draft (L/T) NO LCG from midships/length YES Draft 0.67*Prop. diam YES MPP1 (University of Michigan): computation based on LWL instead of LPP Clarke et al method for course stability, turnability and controllability Lyster and Knights regression results for the estimation of turning circle characteristics Parameter % Difference Advance 28.3 % Transfer 13.0 % Steady Turning Diam % Tactical Diameter 16.5% Steady Speed in Turn/App. Speed 33.3 % Directional Stability (C > 0) YES / NO 17

18 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 18

19 TIME-DOMAIN SIMULATION CODE FOR STANDARD SHIP MANOEUVRES (1) PHP numerical code: Naval Architecture Faculty of the Dunarea de Jos University of Galati, Romania + Department of Naval Architecture, Ocean and Environmental Engineering of the University of Trieste, Italy Validated by the experimental tests Only few full nonlinear simulation models of merchant vessels e.g. VLCC tanker, ro-ro passenger, containership, ferry, etc. known in literature PMM EXPERIMENTS HYDRODYN. DERIVATIVES INPUT IN THE SIMULATION CODE 19

20 TIME-DOMAIN SIMULATION CODE FOR STANDARD SHIP MANOEUVRES (2) CHARACTERISTICS SIMUL. CODE TRIBON MPP1 IMO Advance/L [m] Transfer/L [m] Tactical diameter/l [m] Steady diameter/l [m] Steady drift angle [deg] Speed/Approach speed Stability criterion, C ve - ve - CHARACTERISTICS SIMUL. CODE EXPER. TRIBON IMO 1 st overshoot angle [deg] nd overshoot angle [deg] Initial turning time [sec] Time to 1 st max. heading [sec] Reach time [sec] CHARACTERISTIC SIMUL. CODE EXPER. TRIBON MPP1 Vessel condition stable stable stable unstable Port 30 δ,ψ(deg) 25 Port t(s) Starboard First overshoot angle 8 ψ (deg/s) δ (deg) Simulation code Experiment Tribon M2 δ ψ (Simulation code) ψ (Experiment) Second overshoot angle (Experiment) Second overshoot angle (Simulation code) 20 Starboard

21 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 21

22 1. Offset file CFD TECHNIQUES IN MANOEUVRING u u i = 0 3. Boundary conditions No slip Slip Inflow Outflow uin i = 0 ui = 0 ξ B ui u = const. i = 0 ξ B p p ξ B = 0 p ξ B = 0 p ξ B = 0 p = 0 2. Grid generation bare hull: 2.02 mil cells appended hull: 2.4 mil cells 22

23 SIMULATIONS AT DIFFERENT DRIFT ANGLES Three drift angles (β = 0, 3, 6 ) to determine the hydrodynamic forces acting on the bare hull Existence of the free surface neglected (reduction of computational time) (1) β[deg] (2) Fx_visc, Fy_visc [kn] Fx_visc Fy_visc (1) Velocity field around the hull at 0 drfit angle (2) Velocity field around the hull at 3 drfit angle (3) Velocity field around the hull at 6 drfit angle 23 (3)

24 SIMULATIONS AT DIFFERENT DRIFT AND RUDDER ANGLES simulation cases: RUDDER ANGLE (δ) 0 deg. 10 deg. 20 deg. 30 deg. DRIFT ANGLE (β) 0 deg. 3 deg. 6 deg. 0 deg. -3 deg. 3 deg. -6 deg. 6 deg. 0 deg. -3 deg. 3 deg. -6 deg. 6 deg. 0 deg. -3 deg. 3 deg. -6 deg. 6 deg. free surface elevation at 0 /0 condition WAVE HEIGHT z = 0.035*25 = 0.88 m 24

25 VARIATION OF HYDRODYNAMIC PRESSURE ACTING ON THE RUDDER A small top rudder in the upper part simplification of the grid generation of the stern part 0 deflection, 0 drift 0 deflection, 3 drift 0 deflection, 6 drift 10 deflection, 0 drift 10 deflection, 3 drift 10 deflection, 6 drift 20 deflection, 0 drift 20 deflection, 3 drift 20 deflection, 6 drift 30 deflection, 0 drift 30 deflection, 3 drift 30 deflection, 6 drift 25

26 MATHEMAT. MODEL STANDARD MANOEUVRES OF THE SHIP IMO STANDARDS AND REGULATIONS GENERAL CHARACTER. OF THE FISHING VESSEL RUDDER DESIGN AND HYDRODYN. PERFORMANCE MANOEUV. AT THE INITIAL DESIGN STAGE TIME-DOMAIN SIMULATION CODE CFD TECHNIQUES IN MANOEUVRING CON CLU SION 26

27 CONCLUSIONS 1. INITIAL DESIGN PROGRAMS Q: Input data of main dimensions only, enough? A: No. Significant differences, especially for unsual hullforms. REMARK: more research needed 2. SIMULATION CODES BASED ON HYDRODYNAMIC DERIVATIVES Satisfactory agreement between numerical and experimental results Miscellaneous influence of derivatives on standard manoeuvres parameters Model testsneededto obtaintheinputdata for thecode 3. CFD TECHIQUES IN MANOEUVRING Determination of pressure and velocity spectra around the hull and rudder Base of further computation of hydrodynamic derivatives 27

28 THANK YOU Sail successfully into the future!!! 28