Design Tools & Codes Technology Viability Jason Jonkman, Ph.D. NREL/NWTC 303-384-7026 jason.jonkman@nrel.gov March 11, 2010

Modeling Requirements Coupled aero-hydro-servo-elastic interaction Wind-inflow Discrete events Turbulence Waves Regular Irregular Aerodynamics Induction Rotational augmentation Skewed wake Dynamic stall Hydrodynamics Diffraction Radiation Hydrostatics Structural dynamics Gravity / inertia Elasticity Foundations / moorings Control system Yaw, torque, pitch

What are Design Tools & Codes? Codes developed for direct application in the design process Preprocessors, simulators, & post-processors Primary (simulation) codes are Multi-physics models (aero-hydro-servo-elastic) Full-system models (foundation + substructure + tower + nacelle + drivetrain + rotor) Developed uniquely to the wind application (not general purpose) Codes developed to run on standard PCs (not supercomputers) Code accuracy is only as good as the input Input must be tuned with test data to ensure accurate output

Statement of the Problem Design codes are fundamental to the design of wind turbines Program-developed codes are the industry standard Improvements are key for developing better technology Larger sizes Unique architectures Novel control devices Offshore support structures Innovation is essential for COE reductions & reliability improvements Robust analysis capability is required to develop innovative technology Enhanced analysis capability, accuracy, & speed are essential for achieving DOE goals of reduced COE & improved reliability

Technical Approach Current Emphasis Develop & disseminate enhanced codes Base priorities on user feedback & strategic initiatives Collaborate under Risø-DTU MOU & CENER CRADA Provide technical support to the wind industry Current Emphasis

Schedule & Budget The project is ongoing with no planned completion date Milestones for FY2010 3/31/2010: Release updated version of WT_Perf 3/31/2010: Release updated versions of AeroDyn, FAST, & A2AD with improved interface 4/30/2010: Publish and present paper on BModes at 2010 AIAA SDM conference Note: In FY2009, the reported budget includes funding for both the “Design Tools & Codes” & “Systems Analysis” subtasks; the “Systems Analysis” subtask started & ended in FY2008 with J. Jonkman as the PI & was used to support a portion of the GRC analysis not normally supported under the “Design Tools & Codes” subtask Note: In FY2010, the reported budget includes funding for both the “Design Tools and Codes” and “AeroDyn Development” subtasks; the “AeroDyn Development subtask is new to FY2010 with G. Bir as the PI Budget History FY2008 FY2009 FY2010 DOE Cost-share $750K $0 $835K $850K Key Staff

Accomplishments / Progress – WT_Perf WT_Perf Overview Calculates steady-state rotor performance Inputs are rotor geometry, airfoil data, wind, pitch, & rotor speed Uses BEM theory Recent Accomplishments Added rotor performance optimization algorithm (Harp_Opt) Current Activities Improve solution algorithm Introduce cavitation onset check K. Johnson, NREL Power Coefficient for the CART2

Accomplishments / Progress – AeroDyn AeroDyn Overview Computes aerodynamics (lift, drag, pitch) as part of the aero-elastic solution Wind-inflow input Uniform, unsteady Turbulent (TurbSim) Wake modeling BEM (quasi-steady) GDW (dynamic) Dynamic stall modeling Beddoes-Leishman (semi-empirical) Recent Accomplishments Initiated overhaul to improve interfaces, functionality, & usability Hosted kick-off meeting with 50 attendees Current Activities Improve interface to structural modules Rework theory basis Burton, et al (2001) BEM Discretization

Accomplishments / Progress – HydroDyn HydroDyn Overview Computes wave-kinematics & hydrodynamics as part of the hydro-elastic solution Waves & currents Regular or irregular linear waves Steady sub-surface, near-surface, & depth-independent currents Hydrodynamics Morison’s equation for monopiles Linear radiation/diffraction theory for floating platforms Moorings Quasi-static (nonlinear catenary equations) Recent Accomplishments Published Wind Energy article summarizing development & verification Current Activities Add 2nd-order irregular waves for monopiles (with UT-Austin) Improve interface to structural modules Publish users guide Floating Wind Turbine Concepts

Accomplishments / Progress – FAST FAST Overview Computes structural & control-system responses as part of the aero-hydro-servo-elastic solution Combined modal & MBS formulation through 24 DOFs Controls through subroutines, DLLs, or Simulink® Nonlinear time-domain solution for loads analysis Linearization for controls & stability analysis Preprocessor for building turbine models in MSC.ADAMS Current Activities Add two mass dampers DOFs (with UMass) Add earthquake excitation module (with UC-San Diego) Include more built-in control options Include new output functionality Improve FAST-to-ADAMS generation of curved & swept blades DOFs for a 3-Bladed Turbine

Accomplishments / Progress – A2AD A2AD & MSC.ADAMS Overview Commercial product from MSC Software Computes structural & control-system responses as part of the aero-hydro-servo-elastic solution MBS formulation with unlimited DOFs Controls through subroutines or DLLs Nonlinear time-domain solution Linearization of nonrotating system Datasets can be created by FAST Bypasses some limitations of FAST Current Activities Same as for FAST, plus Restructure A2AD for improved numerical processing Model Created by FAST

Accomplishments / Progress – BModes BModes Overview Computes modal dynamics of blades & towers Inputs are the boundary conditions & distributed isotropic beam properties Considers axial-flap-lag-torsion coupling Uses a 15-DOF FE specially developed to handle rotation-related terms Recent Accomplishments Added modeling of flexible foundations, monopiles, & floating platforms Published paper on modal dynamics at 2008 OMAE conference Current Activities Add gravitational effects for towers Publish verification results at 2010 AIAA SDM conference Mode Shapes of Land-Based NREL 5-MW Tower

Accomplishments / Progress – MCrunch MCrunch Overview A MATLAB®-based postprocessor for data analysis Merges features from legacy codes (Crunch, GPP, GenStats, & Fatigue) Scales, offsets, & calculated channels Statistics Probability density functions Power spectral density Plotting Recent Accomplishments First released in FY2008 Current Activities Modularize for improved efficiency Add rainflow counting, DELs, & lifetime damage for fatigue analysis Add extreme event tables for ultimate analysis Example Outputs from MCrunch

Accomplishments / Progress – Support Technical Support Overview Support offered through Supplying of updated codes, including source Publishing user’s guides Online Q&A forum Phone & e-mail Solicitation of user requirements Workshops Recent Accomplishments Hosted workshop with 47 attendees NWTC Design Codes Website NWTC Design Codes Forum

Accomplishments / Progress – Collaborations CENER CRADA Established in FY2007 for shared code development & testing Cooperation in IEA Task 23 OC3 Collaboration with AeroDyn overhaul, FAST upgrades, MCrunch testing, & floating system analysis Risø-DTU MOU Collaboration currently limited to cooperation within OC3 & UpWind To further collaboration, 2 NREL staff will spend 3 months at Risø-DTU beginning April 2010 Topics of discussion Shared code development Modularization & co-simulation of codes Offshore wind turbine conceptual design & analysis Site-specific inflow characterization Establishment of a CRADA

Proposed Next Steps Project’s biggest challenge Future opportunities User demand for improvements greatly exceeds current staff resources Future opportunities Implement coupled flap-lag-torsion modes in FAST Add FAST animation functionality Allow anisotropic materials & blade curve & sweep in BModes & FAST Merge rigid- & flexible-bodies within MBS models Support detailed gearbox modeling Introduce higher fidelity aerodynamic models e.g., vortex wake models Improve modeling of offshore floating turbines Introduce modeling of offshore fixed-bottom space frames (tripods, jackets) Introduce modeling of smart blades e.g., deformable trailing edge Modularization & co-simulation of codes G. Bir, NREL