Engineering topics

Hayman, Gregory

Publications and source records attributed to Hayman, Gregory.

4 records

DOE OSTI2019

The Unsteady Aerodynamics Module For FAST8

The new modularization framework of FAST v.8 (Jonkman 2013) was accompanied by a complete overhaul of the aerodynamics routines. AeroDyn is an aerodynamics module comprised of four submodels: rotor wake/induction, blade airfoil aerodynamics, tower influence on the blade nodes, and tower drag. Throughout the software overhaul, several improvements to the original theoretical treatments were achieved, including more accurate skewed-wake and unsteady airfoil aerodynamics, and the possibility of modeling highly flexible and curved blades. Under asymmetric conditions, such as wind shear, yawed, and tilted flow, the individual blade elements undergo variations in angle of attack that lead to unsteady aerodynamics phenomena, which can no longer be captured through the static airfoil lift and drag look-up tables. This document covers the main theory and the organization of the modularization framework of the new unsteady aerodynamics submodule (UAM)1, which includes unsteady aerodynamics under attached flow conditions and dynamic stall. The UAM can be called by either blade element momentum theory (only interface discussed in this report), or other future wake models (e.g., dynamic blade element momentum theory, or generalized dynamic wake).

17 WIND ENERGY↗

DOE OSTI2018

Full-System Linearization for Floating Offshore Wind Turbines in OpenFAST: Preprint

The wind engineering community relies on multiphysics engineering software to run nonlinear time-domain simulations, e.g. for design-standards-based loads analysis. Although most physics involved in wind energy are nonlinear, linearization of the underlying nonlinear system equations is often advantageous to understand the system properties and exploit well-established methods and tools for analyzing linear systems. This paper presents the development of the new linearization functionality of the open-source engineering tool OpenFAST for floating offshore wind turbines (FOWTs), as well as the concepts and mathematical background needed to understand and apply it correctly.

17 WIND ENERGY↗

DOE OSTI2018

Full-System Linearization for Floating Offshore Wind Turbines in OpenFAST

The wind engineering community relies on multiphysics engineering software to run nonlinear time-domain simulations (e.g., for design-standards-based loads analysis). Although most physics involved in wind energy are nonlinear, linearization of the underlying nonlinear system equations is often advantageous to understand the system properties and exploit well-established methods and tools for analyzing linear systems. This paper presents the development of the new linearization functionality of the open-source engineering tool OpenFAST for floating offshore wind turbines, as well as the concepts and mathematical background needed to understand and apply it.

17 WIND ENERGY↗

DOE OSTI2018

KiteFAST

KiteFAST is a simulator for airborne wind energy systems based on NREL's OpenFAST whole turbine simulator. KiteFAST is a multi-physics engineering tool for modeling the coupled aero-servo-elastic dynamics of airborne wind energy systems i.e. a wind-energy kite. The engineering model is like NREL's OpenFAST tool for land-based or offshore horizontal-axis wind turbines atop towers, in that KiteFAST models the important physical phenomena and system couplings, including the wind/aerodynamic excitation and full-system dynamics response (fuselage, wings, tail, stabilizers, pylons, nacelles, rotors, tether, ground station, control surfaces, and controller) under both normal (for fatigue) and extreme (for ultimate) loading conditions. The configuration of the wind-energy kite is assumed to have one fuselage; two wings (starboard, port) attached to the fuselage; one vertical stabilizer attached the fuselage; two horizontal stabilizers (starboard, port) attached to the vertical stabilizer; one or more pylons per wing, each with two rotors (top, bottom); one ground-station-fixed tether with a bridal connection to the wings, and nominal circular motion of the energy kite in the port (left) direction. The general configuration of the control surfaces assumes one or more flaps per wing, two rudders on the vertical stabilizer, two elevators per horizontal stabilizer, and rotors with variable speed and rotor-collective blade pitch. KiteFAST was developed from (1) the existing MBDyn open-source multi-body dynamics code; (2) the existing/modified OpenFAST modules NWTC Subroutine Library, AirfoilInfo, InflowWind, MoorDyn, and TurbSim; and (3) new source code for a) generating MBDyn models of the energy kite (KiteMBDyn Preprocessor), b) computing quasi-steady energy-kite aerodynamics (KiteAeroDyn, KiteAeroDyn Driver, KiteVSM, ActuatorDisk), c) interfacing an energy-kite controller, and d) coupling the various KiteFAST modules together (KiteFASTMBD).

Jonkman, Jason↗