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Abstract The variety of configurations for vertical-axis wind turbines (VAWTs) make the development of universal scaling relationships for even basic performance parameters difficult. Rotor geometry changes can be characterized using the concept of solidity, defined as the ratio of solid rotor area to the swept area. However, few studies have explored the effect of this parameter at full-scale conditions due to the challenge of matching both the non-dimensional rotational rate (or tip speed ratio) and scale (or Reynolds number) in conventional wind tunnels. In this study, experiments were conducted on a VAWT model using a specialized compressed-air wind tunnel where the density can be increased to over 200 times atmospheric air. The number of blades on the model was altered to explore how solidity affects performance while keeping other geometric parameters, such as the ratio of blade chord to rotor radius, the same. These data were collected at conditions relevant to the field-scale VAWT but in the controlled environment of the lab. For the three highest solidity rotors (using the most blades), performance was found to depend similarly on the Reynolds number, despite changes in rotational effects. This result has direct implications for the modelling and design of high-solidity field-scale VAWTs.
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Design and Performance of an Ultra-Compact Low-Speed Low-Turbulence Level Wind Tunnel for Aerodynamic and Animal Flight Experiments
The paper presents a novel closed-circuit ultra-compact wind tunnel with an 8:1 contraction ratio and high flow quality. Its key design features include a 2D-type main diffuser, a minimum length contraction, and a screened expanding vane cascade in the last corner. These features reduce the overall tunnel footprint area to less than half of the area of a conventional tunnel design with the same test section size and same contraction ratio. The test section turbulence level is a very low 0.03% over a 4Hz–8500Hz bandwidth.
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- Award ID(s):
- 1725935
- PAR ID:
- 10168994
- Date Published:
- Journal Name:
- AIAA AVIATION 2020 Forum
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.2514/6.2020-3107
