dynamic analysis of an offshore floating wind turbine - review2 -27march2014

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Dynamic analysis of an offshore floating wind turbine M.Tech Project Review – 2 Date 27March 2014 Indian Maritime University, Visakhapatnam Campus Gandhigram, Visakhapatnam - 530 005 Andhra Pradesh, India

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Dynamic analysis of an offshore floating wind turbine

Dynamic analysis of an offshore floating wind turbine

M.Tech Project Review 2Date 27March 2014Indian Maritime University, Visakhapatnam CampusGandhigram, Visakhapatnam - 530 005Andhra Pradesh, IndiaConceptual Wind Turbine Data

Wind loads acting on the top-structure:Load cases acting on the top-structure, composed by the tower and rotor nacelle assembly (RNA), are to be defined in terms of wind conditions for the specific site, according to IEC 61400-1.

These conditions are referring to wind models for:

ECD: Extreme coherent gust with direction change EDC: Extreme direction change EOG: Extreme operating gust EWM: Extreme wind speed model EWS: Extreme wind shear NTM: Normal turbulence model ETM: Extreme turbulence model NWP: Normal wind profile modelConceptual Floater (Spar Buoy) Data

Blade Structural Properties

Blade Structural and Aerodynamic Properties

Conceptual Hub and Drive Train Properties

Conceptual Tower Properties

Hydrodynamic Analysis in ANSYS AQWA(Hydrodynamic Diffraction-Panel Method )

The main requirements for Work Bench Aqwa

Each vessel (or structure) is represented as a single part, as generated in Design Modeler. The panel model must be such that the mesh is up to the waterline. The water line defines the global vertical origin for the analysis. Radiation/Diffraction Analysis Stages WB HD for the diffraction analysis consists of five stages Insert HD system and associate geometry Add Aqwa specific parameters Add Aqwa specific elements Mesh Analysis and post-processing What is Aqwa? Aqwa is a modularised, fully integrated hydrodynamics analysis suite based around 3-D diffraction/radiation methods. ANSYS Workbench implementation provides hydrodynamic diffraction and time domain simulations.

ANSYS Aqwa Capabilities & Applications

ANSYS Aqwa Capabilities Diffraction/Radiation including Morison elements Frequency domain analysis Stability including mooring lines Time domain with irregular waves Time domain with non-linear survival waves Coupled cable dynamics Multiple hydrodynamic interaction and articulations (up to 50 structures) Transfer of motions and pressures to ASAS & ANSYS FE models ANSYS Aqwa Applications Determination of RAOs Wave bending moments Splitting Force calculations for Semi-Submersibles Design and analysis of mooring systems Time history of motions Determination of Air Gaps Calculation of Shielding Effects of ships and barriers Multiple Body Interactions Coupled mooring line-structure interaction Cable Dynamics with intermediate buoys TLP tether analysis Theory in Aqwa

Wave Forces for Diffracting Structures (modelled with plate elements) Incident wave force (Froude-Krylov force): from the pressure in the undisturbed waves. Diffraction force: due to stationary structure disturbing the incident waves. Radiation force: due to structures oscillation which generates waves. Drift force (net force due to high order effect) Theory in Aqwa3D Potential Theory solution Viscous forces are not taken into account Ideal fluid, irrotational, incompressible Small wave elevation Boundary condition problem is solved by satisfying Body Boundary condition (Timman-Newman relations) Linearized free surface condition Sea bed boundary condition Radiation condition Solution for diffracted and radiated wave potentials uses a pulsating source distribution (zero speed solution with forward speed corrections) Theory applies to finite depth and diffraction problem is solved in frequency domain Shallow water solution is available Both 1st Order and 2nd Order wave forces are calculated 2nd Order forces can be calculated from either near field or far field solutions Analysis Results

Analysis Results Object NamePoint MassStateFully DefinedDetails of Point MassVisibilityVisibleSuppressedNot SuppressedX0 mY0 mZ-89.92 mMass definitionManualMass8225420.80078125 kgDefine inertia values byDirect input of InertiaKxx22.6746076004814 mKyy22.6746076004814 mKzz4.46794186739206 mIxx4229000000 kg.mIxy0 kg.mIxz0 kg.mIyy4229000000 kg.mIyz0 kg.mIzz164200000 kg.mObject NameMeshStateMeshedDetails of MeshDefeaturing Tolerance0.9 mMax Element Size2 mMax Allowed Frequency0.361 HzMeshing TypeProgram ControlledGenerated Mesh InformationNumber of Nodes3858Number of Elements3894Number of Nodes (Diffracting Bodies)2910Number of Elements (Diffracting Bodies)2896Analysis Results Object NameWave DirectionsStateFully DefinedDetails of Wave DirectionsTypeRange of Directions, No Forward SpeedForward Speed0 m/sRequired Wave InputWave Range-180 to 180 (-PI to PI)Interval45 Number of Intermediate Directions7Optional Wave Directions AAdditional RangeNoneOptional Wave Directions BAdditional RangeNoneOptional Wave Directions CAdditional RangeNoneOptional Wave Directions DAdditional RangeNoneObject NameWave FrequenciesStateFully DefinedDetails of Wave FrequenciesFrequency / Period definitionRangeManual DefinitionDefinition TypeRangeLowest Frequency0.007 HzLongest Period142.809 sHighest Frequency0.228 HzShortest Period4.386 sInterval TypeFrequencyInterval Frequency0.012 HzNumber of Intermediate Values17Additional Frequencies AAdditional RangeNoneAdditional Frequencies BAdditional RangeNoneAdditional Frequencies CAdditional RangeNoneAdditional Frequencies DAdditional RangeNonePressure and Motions

Radiation Damping &Diffraction Forces

Radiation Damping Diffraction Forces Hydrostatic Particulars G L O B A L P A R A M E T E R WATER DEPTH = 500.000mDENSITY OF WATER = 1025.000kg/m3ACCELERATION DUE TO GRAVITY = 9.807m/s2 X Y ZCENTRE OF GRAVITY 0.000 0.000 -89.920

INERTIA MATRIX 4.229E+09 0.000E+00 0.000E+00

0.000E+00 4.229E+09 0.000E+00

0.000E+00 0.000E+00 1.642E+08 STIFFNESS MATRIX AT THE CENTRE OF GRAVITY C.O.G GX= 0.000 GY= 0.000 GZ= -89.920HEAVE( Z) = 3.306E+05 -2.468E-01 6.165E-01ROLL(RX) = -2.468E-01 2.242E+09 -8.388E-03PITCH(RY) = 6.165E-01 -8.388E-03 2.242E+09 HYDROSTATIC DISPLACEMENT PROPERTIES --------------------------------------

MESH BASED DISPLACEMENT . . . . . . . . = 7.97689E+03 MASS BASED DISPLACEMENT . . . . . . . . = 8.02480E+03

POSITION OF THE CENTRE OF BUOYANCY BX = 0.000 BY = 0.000 BZ = -61.973

AN INCOMPLETE ELEMENT DESCRIPTION OF FX = 0.000 THE HULL GIVES OUT OF BALANCE FORCES FY = 0.000 AND MOMENTS. IF THE C.O.B. IS NOT FZ = -0.006 BELOW THE C.O.G. THIS GIVES OUT OF MX = 0.000 BALANCE MOMENTS (FORCES ARE DIVIDED MY = 0.000 BY THE WEIGHT AND ARE W.R.T. AXES MZ = 0.000 PARALLEL TO THE FIXED REFERENCE AXES) CUT WATER PLANE AREA . . . . . . . . . . . = 3.289E+01CENTRE OF FLOATATION. I.E. CENTROID X = 0.000POSITION IN THE FIXED REFERENCE AX ES Y = 0.000PRINCIPAL SECOND MOMENTS OF AREA IXX= 8.609E+01 IYY= 8.609E+014. SMALL ANGLE STABILITY PARAMETERS -----------------------------------DISTANCE BETWEEN C.O.G. AND C.O.B BG = -27.947METACENTRIC HEIGHTS WITH RESPECT TO GMX= 27.958THE PRINCIPAL AXES OF THE CUT AREA GMY= 27.958DISTANCE BETWEEN THE C.O.B. AND THE BMX= 0.011METACENTRE (BMX=GMX+BG,BMY=GMY+BG) BMY= 0.011RESTORING MOMENT ABOUT THE PRINCIPAL MX = 3.913E+07AXES PER DEGREE ROTATION MY = 3.913E+07ADDED MASS-VARIATION WITH WAVE PERIOD/FREQUENCY ADDED MASS-VARIATION WITH WAVE PERIOD/FREQUENCY PERIOD FREQ M M M M M M M M M M M M (SECS)(RAD/S) 11 22 33 44 55 66 13 15 24 26 35 46 ----------------------------------------------------------------------------------------------------------------------------------- 142.8 0.044 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -8.34E-01 2.42E+08 -2.42E+08 -4.13E-02 -5.56E+01 1.57E+00 135.3 0.046 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -6.71E-01 2.42E+08 -2.42E+08 -4.08E-02 -4.90E+01 1.52E+00 127.8 0.049 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -7.06E-01 2.42E+08 -2.42E+08 -4.08E-02 -5.26E+01 1.54E+00 120.3 0.052 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -6.69E-01 2.42E+08 -2.42E+08 -4.11E-02 -4.52E+01 1.54E+00 112.7 0.056 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -6.47E-01 2.42E+08 -2.42E+08 -4.08E-02 -4.91E+01 1.54E+00 105.2 0.060 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -6.94E-01 2.42E+08 -2.42E+08 -4.09E-02 -5.15E+01 1.55E+00 97.71 0.064 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -6.94E-01 2.42E+08 -2.42E+08 -4.09E-02 -4.85E+01 1.53E+00 90.19 0.070 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -7.13E-01 2.42E+08 -2.42E+08 -4.09E-02 -4.55E+01 1.55E+00 82.68 0.076 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -7.78E-01 2.42E+08 -2.42E+08 -4.10E-02 -4.76E+01 1.55E+00 75.16 0.084 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -7.24E-01 2.42E+08 -2.42E+08 -4.11E-02 -4.60E+01 1.55E+00 67.65 0.093 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -7.65E-01 2.42E+08 -2.42E+08 -4.09E-02 -5.32E+01 1.55E+00 60.13 0.104 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -7.35E-01 2.42E+08 -2.42E+08 -4.07E-02 -5.29E+01 1.53E+00 52.61 0.119 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -7.62E-01 2.42E+08 -2.42E+08 -4.07E-02 -5.23E+01 1.54E+00 45.10 0.139 8.34E+06 8.34E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -6.42E-01 2.42E+08 -2.42E+08 -4.10E-02 -5.55E+01 1.56E+00 37.58 0.167 8.35E+06 8.35E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -5.69E-01 2.43E+08 -2.43E+08 -4.10E-02 -5.36E+01 1.54E+00 30.06 0.209 8.35E+06 8.35E+06 2.61E+05 1.58E+10 1.58E+10 4.68E+00 -6.30E-01 2.43E+08 -2.43E+08 -4.09E-02 -3.63E+01 1.55E+00 22.55 0.279 8.37E+06 8.37E+06 2.63E+05 1.59E+10 1.59E+10 4.68E+00 -6.02E-01 2.44E+08 -2.44E+08 -4.15E-02 -7.79E+00 1.58E+00 15.03 0.418 8.40E+06 8.40E+06 2.66E+05 1.61E+10 1.61E+10 4.68E+00 -8.66E-01 2.47E+08 -2.47E+08 -4.17E-02 1.55E+01 1.60E+00 4.39 1.433 8.08E+06 8.08E+06 2.44E+05 1.45E+10 1.45E+10 4.68E+00 -8.35E-01 2.24E+08 -2.24E+08 -3.71E-02 -3.26E+01 1.26E+00DAMPING-VARIATION WITH WAVE PERIOD/FREQUENCYDAMPING-VARIATION WITH WAVE PERIOD/FREQUENCY -------------------------------------------- PERIOD FREQ C C C C C C C C C C C C (SECS)(RAD/S) 11 22 33 44 55 66 13 15 24 26 35 46 ----------------------------------------------------------------------------------------------------------------------------------- 142.8 0.044 1.28E+00 1.27E+00 2.39E+01 1.05E+03 1.04E+03 4.10E-08 -9.78E-06 3.64E+01 -3.66E+01 1.46E-08 8.00E-02 -9.73E-07 135.3 0.046 1.52E+00 1.51E+00 2.52E+01 1.25E+03 1.25E+03 4.34E-08 1.84E-04 4.35E+01 -4.35E+01 -6.71E-08 1.33E-01 2.00E-06 127.8 0.049 1.82E+00 1.82E+00 2.66E+01 1.50E+03 1.51E+03 4.64E-08 1.79E-04 5.24E+01 -5.21E+01 -1.72E-08 -2.17E-02 -1.04E-06 120.3 0.052 2.20E+00 2.21E+00 2.81E+01 1.83E+03 1.83E+03 4.97E-08 3.62E-05 6.35E+01 -6.35E+01 6.78E-08 8.75E-02 -1.48E-06 112.7 0.056 2.72E+00 2.72E+00 2.99E+01 2.26E+03 2.27E+03 5.35E-08 6.39E-04 7.84E+01 -7.84E+01 -3.65E-08 -1.48E-02 2.37E-06 105.2 0.060 3.40E+00 3.41E+00 3.18E+01 2.84E+03 2.86E+03 5.80E-08 -7.13E-04 9.86E+01 -9.84E+01 -2.08E-08 6.92E-02 1.07E-06 97.71 0.064 4.35E+00 4.37E+00 3.40E+01 3.65E+03 3.65E+03 6.35E-08 -1.93E-05 1.26E+02 -1.26E+02 9.25E-08 3.36E-02 -3.32E-06 90.19 0.070 5.71E+00 5.72E+00 3.65E+01 4.80E+03 4.81E+03 7.00E-08 3.41E-04 1.66E+02 -1.65E+02 -2.74E-07 6.12E-02 5.33E-06 82.68 0.076 7.71E+00 7.71E+00 3.92E+01 6.52E+03 6.54E+03 7.78E-08 -8.26E-04 2.24E+02 -2.24E+02 -1.27E-07 6.02E-02 4.16E-06 75.16 0.084 1.08E+01 1.08E+01 4.24E+01 9.21E+03 9.19E+03 8.86E-08 -2.37E-05 3.15E+02 -3.15E+02 -1.30E-07 8.23E-02 7.49E-08 67.65 0.093 1.58E+01 1.58E+01 4.58E+01 1.37E+04 1.37E+04 1.03E-07 -2.70E-04 4.65E+02 -4.65E+02 1.96E-07 2.23E-01 2.52E-06 60.13 0.104 2.49E+01 2.49E+01 4.93E+01 2.18E+04 2.18E+04 1.23E-07 -3.47E-04 7.36E+02 -7.36E+02 3.06E-07 5.93E-03 -3.01E-06 52.61 0.119 4.28E+01 4.28E+01 5.24E+01 3.85E+04 3.85E+04 1.53E-07 -3.55E-04 1.28E+03 -1.28E+03 -6.35E-09 1.80E-01 4.56E-06 45.10 0.139 8.50E+01 8.50E+01 5.28E+01 7.94E+04 7.94E+04 2.04E-07 -3.42E-04 2.60E+03 -2.60E+03 -1.02E-06 3.85E-01 1.57E-05 37.58 0.167 2.11E+02 2.11E+02 4.39E+01 2.10E+05 2.10E+05 3.03E-07 5.49E-03 6.66E+03 -6.66E+03 -9.73E-07 3.11E-01 3.77E-05 30.06 0.209 7.44E+02 7.44E+02 1.21E+01 8.25E+05 8.25E+05 5.26E-07 9.66E-04 2.48E+04 -2.48E+04 -1.60E-06 1.70E-01 8.75E-05 22.55 0.279 3.83E+03 3.83E+03 7.72E+01 5.26E+06 5.26E+06 1.01E-06 -6.16E-03 1.42E+05 -1.42E+05 -2.39E-05 -6.50E-01 8.92E-04 15.03 0.418 2.57E+04 2.57E+04 2.27E+03 5.66E+07 5.66E+07 2.32E-06 4.16E-03 1.21E+06 -1.21E+06 -1.57E-04 -7.94E+00 6.97E-03 4.39 1.433 4.18E+05 4.18E+05 5.48E+03 2.94E+09 2.94E+09 8.45E-05 -6.07E-02 3.51E+07 -3.51E+07 2.15E-04 -2.14E+00 -1.80E-021Diffraction (Phase Angle vs Frequency & Direction)

Diffraction (Force/Moment vs Direction)

RAOs (Response Amplitude Operators) (Distance/Rotation vs Frequency & Direction)

SF/BM (RAO) (Phase Angle vs Frequency)

Future work Time Domain Hydrodynamic analysis of spar-type floater with Mooring Lines (Work on Progress in AQWA) Cable Dynamics (Work On Progress AQWA/ORCAFLEX)Aerodynamic Force Calculations (NTNU Mat Lab Code) Coupled aero-servo-hydro-elastic simulation (NTNU Mat lab Code) Thank You