Nature’s Wind Turbines: The Measured Aerodynamic Efficiency of Spinning Seeds Approaches Theoretical Limits
This paper describe a procedure to measure experimentally the power coefficient, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>C</mi><mi>p</mi></msub></semantics>&...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Biomimetics |
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| Online Access: | https://www.mdpi.com/2313-7673/7/4/161 |
| _version_ | 1797461288460222464 |
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| author | Timothy C. A. Molteno |
| author_facet | Timothy C. A. Molteno |
| author_sort | Timothy C. A. Molteno |
| collection | DOAJ |
| description | This paper describe a procedure to measure experimentally the power coefficient, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>C</mi><mi>p</mi></msub></semantics></math></inline-formula>, of winged seeds, and apply this technique to seeds from the Norway maple (<i>Acer platanoides</i>). We measure <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>p</mi></msub><mo>=</mo><mn>56.9</mn><mo>±</mo><mn>2</mn><mo>%</mo></mrow></semantics></math></inline-formula> at a tip speed ratio of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.21</mn><mo>±</mo><mn>0.06</mn></mrow></semantics></math></inline-formula>. Our results are in agreement with previously published CFD simulations that indicate that these seeds—operating in low-Reynolds number conditions—approach the Betz limit (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>p</mi></msub><mo>=</mo><mn>59.3</mn><mo>%</mo></mrow></semantics></math></inline-formula>) the maximum possible efficiency for a wind turbine. In addition, this result is not consistent with the recent theoretical work of Okulov & Sørensen, which suggests that a single-bladed turbine with a tip-speed ratio of 3.2 can achieve a power efficiency of no more than 30%. |
| first_indexed | 2024-03-09T17:17:07Z |
| format | Article |
| id | doaj.art-47b904151d2a468fadea15547c22d13a |
| institution | Directory Open Access Journal |
| issn | 2313-7673 |
| language | English |
| last_indexed | 2024-03-09T17:17:07Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Biomimetics |
| spelling | doaj.art-47b904151d2a468fadea15547c22d13a2023-11-24T13:30:38ZengMDPI AGBiomimetics2313-76732022-10-017416110.3390/biomimetics7040161Nature’s Wind Turbines: The Measured Aerodynamic Efficiency of Spinning Seeds Approaches Theoretical LimitsTimothy C. A. Molteno0Department of Physics, University of Otago, P.O. Box 56, Dunedin 9016, New ZealandThis paper describe a procedure to measure experimentally the power coefficient, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>C</mi><mi>p</mi></msub></semantics></math></inline-formula>, of winged seeds, and apply this technique to seeds from the Norway maple (<i>Acer platanoides</i>). We measure <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>p</mi></msub><mo>=</mo><mn>56.9</mn><mo>±</mo><mn>2</mn><mo>%</mo></mrow></semantics></math></inline-formula> at a tip speed ratio of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.21</mn><mo>±</mo><mn>0.06</mn></mrow></semantics></math></inline-formula>. Our results are in agreement with previously published CFD simulations that indicate that these seeds—operating in low-Reynolds number conditions—approach the Betz limit (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>p</mi></msub><mo>=</mo><mn>59.3</mn><mo>%</mo></mrow></semantics></math></inline-formula>) the maximum possible efficiency for a wind turbine. In addition, this result is not consistent with the recent theoretical work of Okulov & Sørensen, which suggests that a single-bladed turbine with a tip-speed ratio of 3.2 can achieve a power efficiency of no more than 30%.https://www.mdpi.com/2313-7673/7/4/161Betz limitaerodynamic efficiencybiomimicry |
| spellingShingle | Timothy C. A. Molteno Nature’s Wind Turbines: The Measured Aerodynamic Efficiency of Spinning Seeds Approaches Theoretical Limits Biomimetics Betz limit aerodynamic efficiency biomimicry |
| title | Nature’s Wind Turbines: The Measured Aerodynamic Efficiency of Spinning Seeds Approaches Theoretical Limits |
| title_full | Nature’s Wind Turbines: The Measured Aerodynamic Efficiency of Spinning Seeds Approaches Theoretical Limits |
| title_fullStr | Nature’s Wind Turbines: The Measured Aerodynamic Efficiency of Spinning Seeds Approaches Theoretical Limits |
| title_full_unstemmed | Nature’s Wind Turbines: The Measured Aerodynamic Efficiency of Spinning Seeds Approaches Theoretical Limits |
| title_short | Nature’s Wind Turbines: The Measured Aerodynamic Efficiency of Spinning Seeds Approaches Theoretical Limits |
| title_sort | nature s wind turbines the measured aerodynamic efficiency of spinning seeds approaches theoretical limits |
| topic | Betz limit aerodynamic efficiency biomimicry |
| url | https://www.mdpi.com/2313-7673/7/4/161 |
| work_keys_str_mv | AT timothycamolteno natureswindturbinesthemeasuredaerodynamicefficiencyofspinningseedsapproachestheoreticallimits |