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Near-wake structure of full-scale vertical-axis wind turbines
- Publication Year :
- 2021
- Publisher :
- Cambridge University Press, 2021.
-
Abstract
- To design and optimize arrays of vertical-axis wind turbines (VAWTs) for maximal power density and minimal wake losses, a careful consideration of the inherently three-dimensional structure of the wakes of these turbines in real operating conditions is needed. Accordingly, a new volumetric particle-tracking velocimetry method was developed to measure three-dimensional flow fields around full-scale VAWTs in field conditions. Experiments were conducted at the Field Laboratory for Optimized Wind Energy (FLOWE) in Lancaster, CA, using six cameras and artificial snow as tracer particles. Velocity and vorticity measurements were obtained for a 2-kW turbine with five straight blades and a 1-kW turbine with three helical blades, each at two distinct tip-speed ratios and at Reynolds numbers based on the rotor diameter $D$ between $1.26 \times 10^6$ and $1.81 \times 10^6$. A tilted wake was observed to be induced by the helical-bladed turbine. By considering the dynamics of vortex lines shed from the rotating blades, the tilted wake was connected to the geometry of the helical blades. Furthermore, the effects of the tilted wake on a streamwise horseshoe vortex induced by the rotation of the turbine were quantified. Lastly, the implications of these dynamics for the recovery of the wake were examined. This study thus establishes a fluid-mechanical connection between the geometric features of a VAWT and the salient three-dimensional flow characteristics of its near-wake region, which can potentially inform both the design of turbines and the arrangement of turbines into highly efficient arrays.<br />Version 2, currently under review
- Subjects :
- 020209 energy
FOS: Physical sciences
02 engineering and technology
Wake
01 natural sciences
7. Clean energy
Turbine
010305 fluids & plasmas
law.invention
Physics::Fluid Dynamics
symbols.namesake
law
0103 physical sciences
Horseshoe vortex
0202 electrical engineering, electronic engineering, information engineering
Wind power
business.industry
Rotor (electric)
Mechanical Engineering
Fluid Dynamics (physics.flu-dyn)
Reynolds number
Physics - Fluid Dynamics
Mechanics
Vorticity
Condensed Matter Physics
Vortex
Mechanics of Materials
symbols
business
Geology
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....3f4c71cdc57735a5437fb57c6ccce707