Unsteady aerodynamics and vortex shedding of a wind turbine blade

Title

Unsteady aerodynamics and vortex shedding of a wind turbine blade

 Author

Iyer, Sowmya (TU Delft Aerospace Engineering)

Contributor

Ferreira, Carlos (mentor) ORCID 0000-0003-0192-3651
Bertagnolio, Franck (graduation committee)
Grinderslev, Christian (graduation committee)
Yu, W. (graduation committee) ORCID 0000-0001-7829-6129
Xu, G. (graduation committee) ORCID 0000-0002-8520-3055
van Oudheusden, B.W. (graduation committee) ORCID 0000-0002-7255-0867

 Degree granting institution

Delft University of Technology

 Programme

European Wind Energy Masters (EWEM)

 Date

2023-08-25

 Abstract

The thesis presents an analysis of unsteady vortex shedding and vortex induced vibrations (VIV) on wind turbine blades using a combination of Stereoscopic Particle Image Velocimetry (SPIV) and Computational Fluid Dynamics (CFD). A spanwise uniform blade with a symmetric NACA0021 airfoil section, 0.075 m chord, and 0.4 m span was tested experimentally for a static, plunging, and surging blade oscillating at 90 deg angle of attack, 5 Hz, and 2.5 Hz frequency, 1 chord oscillation amplitude. Equivalent CFD simulation cases were run to compare the results and validate the CFD setup, which was used to analyse additional cases of interest. The extent of the three-dimensional flow behaviour due to the tip vortex was described, along with determining the lock-in region for the two motions using additional simulations. The results indicated that the spanwise convection of the tip vortex and the transition to a ‘2D’ flow were only dependent on the blade aspect ratio and independent of the freestream wind speed, the type of motion, and the oscillation frequency. The lock-in region for the plunging and surging blades was presented, noting that all the surging cases were locked in, most likely due to the large oscillation amplitude. However, the surging cases had a positive aerodynamic damping and hence, VIV would not be excited for a freely vibrating blade. It is suggested as future work to test a flexible blade and study the onset and development of VIV.

 Subject

Vortex induced vibrations
Vortex Induced Motion
Flow visualization
CFD
wind tunnel experiment
Wind Turbine Blade
lock-in range
Strouhal number

 To reference this document use:

http://resolver.tudelft.nl/uuid:105bcf3a-8c6d-4dfe-9165-5ba42d415788

 Part of collection

Student theses

 Document type

master thesis

 Rights

© 2023 Sowmya Iyer
Files
PDF MSc_Thesis_EWEM_Rotor_Des ... N_IYER.pdf 91.12 MB
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