DYNAMIC POSITIONING. September 1, Hans Cozijn

Transcription

1 DYNAMIC POSITIONING MARIN SOFTWARE SEMINAR SINGAPORE September 1, 2015 Hans Cozijn Senior Project Manager Offshore

2 STATIONKEEPING USING DYNAMIC POSITIONING 2

3 PRESENTATION OUTLINE Dynamic Positioning Tools for DP Analysis Static Time domain Model tests Improving the Accuracy of Calculation Results Enviromental loads Calibration of numerical models (How) Can MARIN (Software) Help You? On going Research 3

4 PRESENTATION OUTLINE Dynamic Positioning Tools for DP Analysis Static Time domain Model tests Improving the Accuracy of Calculation Results Enviromental loads Calibration of numerical models (How) Can MARIN (Software) Help You? On going Research 4

5 DYNAMIC POSITIONING BASIC PRINCIPLES Vessel Thrusters are Automatically Controlled to Keep the Vessel at the Required Postion and Heading Necessary Components : Position measurement Kalman filter Controller Allocation algorithm Thrusters Power DP Classes DP0 manual operation DP1 automatic, no redundancy DP2, DP3 increased redundancy 5

6 PRESENTATION OUTLINE Dynamic Positioning Tools for DP Analysis Static Time domain Model tests Improving the Accuracy of Calculation Results Enviromental loads Calibration of numerical models (How) Can MARIN (Software) Help You? On going Research 6

7 TOOLS FOR DP ANALYSIS Static DP Capability Calculations PRO : easy to compare cases CON : limited accuracy Time domain Simulations PRO : detailed results Increasing Accuracy CON : more time consuming Increasing Level of Detail DP Model Tests Increasing Complexity Increasing Cost PRO : most accurate prediction CON : relatively expensive Sea Trials PRO : "the real thing" CON : no control over environment 7

8 STATIC DP CAPABILITY CALCULATIONS Static calculations; Mean wind, wave and current forces Mean thruster forces Fixed current Wind wave relation Nodynamic behaviour No stationkeeping accuracy Used din Early Design Stage Thruster configurations Fil Failure cases Stationkeeping Capability Sustained wind speed, presented in polar plot ("footprint") Software : DPCAP / TRUST 8

9 DP TIME DOMAIN SIMULATIONS Time domain Simulations Dynamic wind, wave and current forces Simulation of vessel behaviour in time Optimise DPcontrol settings Workability analysis Accuracy of the Results Depends on Quality of the simulation model Quality of the input data Simulation Results Statistics ti ti of vessel position Statistics of thruster loading Heading window for given sea state Fuel consumption position error heading window drift off max position error Software : anysim heading [deg] 9 1 2

10 DP MODEL TESTS Model Tests Complete physical model + DP system Realistic thruster response Thruster interaction effects Optimise DP control settings Safely investigate limit sea states Identify possible unexpected behaviour Most Realistic Design Verification Model Test Results Statistics of vessel position Statistics of thruster loading Heading window for given sea state Fuel consumption Calibration of numerical models Software : RUNSIM 10

11 PRESENTATION OUTLINE Dynamic Positioning Tools for DP Analysis Static Time domain Model tests Improving the Accuracy of Calculation Results Enviromental loads Calibration of numerical models (How) Can MARIN (Software) Help You? On going Research 11

12 IMPROVING ACCURACY OF CALCULATION RESULTS Accuracy of the Results Depends on Quality of the simulation model Quality of the input data Environmental Loads Wind load coefficients Current load coefficients Wave drift forces Calibration of Numerical Models Roll damping Low frequency damping Thruster interaction effects 12

13 WIND LOAD MEASUREMENTS Wind Tunnel Tests Accurate Results (Load Coefficients) All Physics Included (drag, lift, shielding,...) Check Blockage Effects Check Scale Effects 13

14 CURRENT LOAD MEASUREMENTS Basin Towing Tests Accurate Results (Load Coefficients) All Physics Included (friction, drag, lift,...) Free Surface and Moon Pool Included Check Blockage Effects Check Scale Effects 14

15 ALTERNATIVE APPROACH CFD CALCULATIONS RANS calculations MARIN in house CFD Code ReFRESCO 4,000 Core Computer Cluster Wind and Current Load Calculations 15

16 THRUSTER INTERACTION MEASUREMENTS DuringDP DP Operation the Effective Thrust Force is smaller than the Open Water Bollard Pull Thrust Thruster interaction Losses Thruster hull Thruster thrusterthruster Thruster current Captive Model Tests Effective Force depends on Ai Azimuth thangle Thruster hull Interaction Coefficients used in Time domain Model 16

17 THRUSTER HULL INTERACTION (SEMI SUBMERSIBLE) Obstruction of wake flow by other thruster (#4) Thruster % 80% 60% 40% Obstruction of wake flow by opposite pontoon (Coanda effect) 20% 0% -100% -80% -60% -40% -20% 0% 20% 40% 60% 80% 100% -20% -40% -60% -80% Thrust reduction -100% due to wake flow along ship-hull 17

18 PIV MEASUREMENTS Flow Visualization to Improve Understanding of Physics Deformation of the Wake under the Hull Deflection ofthe Wake at the Bilge ("CoandaEffect") Comparison with ihcfd Calculations Cl l 18

19 PIV MEASUREMENTS Flow Visualization to Improve Understanding of Physics Deformation of the Wake under the Hull Deflection ofthe Wake at the Bilge ("CoandaEffect") Comparison with ihcfd Calculations Cl l 19

20 PRESENTATION OUTLINE Dynamic Positioning Tools for DP Analysis Static Time domain Model tests Improving the Accuracy of Calculation Results Enviromental loads Calibration of numerical models (How) Can MARIN (Software) Help You? On going Research 20

21 (HOW) CAN MARIN (SOFTWARE) HELP YOU? Static DP Capability Analysis Thruster lay out Thruster sizing Time domain Simulations DP control settings Vessel motions + stationkeeping accuracy Fuel consumption DP Model Tests Same as time domain simulations, but more accurate results Demonstration joy stick control Bridge Simulator (?) DP demonstration / training 21

22 PRESENTATION OUTLINE Dynamic Positioning Tools for DP Analysis Static Time domain Model tests Improving the Accuracy of Calculation Results Enviromental loads Calibration of numerical models (How) Can MARIN (Software) Help You? On going Research 22

23 DYNAMIC POSITIONING ONGOING RESEARCH Thruster interaction Effects PIV measurements CFD calculations Advanced Allocation Algorithms Fuel efficiency Stationkeeping accuracy Software Developments Identical DP system for model tests, simulations and bridge simulator Use of commercial DP systems in model tests and bridge simulator opendp JIP Software frame work for DP developments Support DP innovations Discussion, co operation and sharing 23

24 THANK YOU FOR YOUR ATTENTION! Hans Cozijn Senior Project Manager Offshore Tel E mail J.L.Cozijn@MARIN.nl