0
Research Papers: Alternative Energy Sources

Toward Identifying Aeroelastic Mechanisms in Near-Wake Instabilities of Floating Offshore Wind Turbines

[+] Author and Article Information
Steven N. Rodriguez

Department of Mechanical
Engineering and Mechanics,
Lehigh University,
Bethlehem, PA 18015
e-mail: snr214@lehigh.edu

Justin W. Jaworski

Assistant Professor
Department of Mechanical
Engineering and Mechanics,
Lehigh University,
Bethlehem, PA 18015
e-mail: jaworski@lehigh.edu

Contributed by the Advanced Energy Systems Division of ASME for publication in the JOURNAL OF ENERGY RESOURCES TECHNOLOGY. Manuscript received October 1, 2016; final manuscript received December 21, 2016; published online March 8, 2017. Assoc. Editor: Ryo Amano.

J. Energy Resour. Technol 139(5), 051203 (Mar 08, 2017) (16 pages) Paper No: JERT-16-1391; doi: 10.1115/1.4035753 History: Received October 01, 2016; Revised December 21, 2016

A free-vortex-wake aeroelastic framework evaluates the impact of blade elasticity on the near-wake formation and its linear stability for onshore and offshore configurations of the National Renewable Energy Laboratory (NREL) 5 MW reference wind turbine. Numerical results show that motion of the flexible rotor further destabilizes its tip-vortices through earlier onset of mutual inductance relative to the rigid rotor results for onshore and offshore turbines. The near-wake growth rate is demonstrated to depend on the azimuthal position of the rotor for all cases considered, which appears to not have been reported previously for wake stability analyses in the rotorcraft literature.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Aerodynamic states of a floating offshore wind turbine (left to right): (1) axial inflow, (2) initial rotor–wake interaction, (3) vortex-ring state, and (4) reversed axial inflow [8,9], where T is the rotor thrust

Grahic Jump Location
Fig. 2

Example design configuration of the MIT/NREL floating offshore wind turbine concept [2]

Grahic Jump Location
Fig. 3

MIT/NREL TLP synthetic rigid body motion

Grahic Jump Location
Fig. 4

Illustration of a straight finite filament used in the Biot–Savart integral

Grahic Jump Location
Fig. 5

Inertial coordinate system of FOWT and tip-vortex geometry

Grahic Jump Location
Fig. 6

Schematic of the global reference frame used to compute blade dynamics and elasticity during rigid body motions

Grahic Jump Location
Fig. 7

Blade deflection reference frame, parameters, and degrees-of-freedom

Grahic Jump Location
Fig. 8

Damping decay rate of NREL blade first mode vibration

Grahic Jump Location
Fig. 9

Illustration of blade deflection interaction with the vortex lattice shed into the wake

Grahic Jump Location
Fig. 10

Transition of rotor blade displacements and fluid forces to steady-state: flapwise deflection (left) and rotor thrust (right)

Grahic Jump Location
Fig. 11

Onshore flexible and rigid rotor stability trends for the maximum growth rate α (s−1) of each tip-vortex versus the perturbation wave number ω (rad−1)

Grahic Jump Location
Fig. 12

Onshore flexible and rigid rotor near wake convection

Grahic Jump Location
Fig. 13

Divergence rate fluctuation in time for both rigid and flexible rotors of the onshore base case at wavenumber ω = 1.5 (1/rad)

Grahic Jump Location
Fig. 14

Offshore flexible and rigid rotor stability trends for the maximum growth rate α (s−1) of each tip-vortex versus the perturbation wave number ω (rad−1)

Grahic Jump Location
Fig. 15

Divergence rate fluctuation in time for both rigid and flexible rotors of the MIT/NREL TLP system at wavenumber ω = 1.5 (1/rad)

Grahic Jump Location
Fig. 16

Offshore flexible and rigid rotor near wake convection

Grahic Jump Location
Fig. 17

Offshore and onshore flexible and rigid rotor stability trends at t = 16.67 s for the maximum growth rate α (s−1) of each tip-vortex versus the perturbation wave number ω (rad−1)

Grahic Jump Location
Fig. 18

Divergence rate fluctuation in time for (a) rigid onshore and offshore rotors and (b) flexible onshore and offshore rotors at wave number ω = 1.5 (1/rad)

Grahic Jump Location
Fig. 19

Wake geometry shed from a rigid rotor configuration, t = 16.67 s

Grahic Jump Location
Fig. 20

Wake geometry shed from a flexible rotor configuration, t = 16.67 s

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In