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<front>
<journal-meta>
<journal-id journal-id-type="publisher">WESD</journal-id>
<journal-title-group>
<journal-title>Wind Energy Science Discussions</journal-title>
<abbrev-journal-title abbrev-type="publisher">WESD</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">Wind Energ. Sci. Discuss.</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">2366-7621</issn>
<publisher><publisher-name></publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/wes-2026-111</article-id>
<title-group>
<article-title>Bio-Inspired Outer-Span Hybridization of the NREL Phase VI Rotor for Enhancing Aerodynamic Performance and Flow-Field Stability</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>EL Qamch</surname>
<given-names>Yassine</given-names>
<ext-link>https://orcid.org/0009-0001-0662-0564</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Qaissi</surname>
<given-names>Khaoula</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Ali Omar</surname>
<given-names>Ashraf</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Lahmili</surname>
<given-names>Wafae</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Bouchaala</surname>
<given-names>Kenza</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>International University of Rabat – School of Aerospace and Automotive engineering – Parc Technopolis Rabat –Rocade de     Rabat-Salé 11100 – Sala Al Jadida – Morocco</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Laboratory of Energy, Materials and Sustainable Development, ENSAM, Moulay Ismail University, 15290, Meknes, Morocco</addr-line>
</aff>
<pub-date pub-type="epub">
<day>22</day>
<month>07</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>25</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Yassine EL Qamch et al.</copyright-statement>
<copyright-year>2026</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://wes.copernicus.org/preprints/wes-2026-111/">This article is available from https://wes.copernicus.org/preprints/wes-2026-111/</self-uri>
<self-uri xlink:href="https://wes.copernicus.org/preprints/wes-2026-111/wes-2026-111.pdf">The full text article is available as a PDF file from https://wes.copernicus.org/preprints/wes-2026-111/wes-2026-111.pdf</self-uri>
<abstract>
<p>The presenting work evaluates a selective bio-inspired outer-span hybridization of the NREL Phase VI wind turbine rotor. An owl-inspired airfoil (OA-T), obtained through controlled thickness scaling of a reconstructed owl-wing section, is integrated over the outer 20 % of the blade span while preserving the original chord and twist distributions. The objective is to assess whether localized geometric modification in the torque-dominant tip region can improve aerodynamic performance under increasing loading. A validated CFD framework is employed at both airfoil and rotor scales. Transition SST simulations reproduce the experimental lift behavior of the owl-inspired airfoil, while steady RANS&amp;ndash;MRF simulations capture the torque response of the baseline Phase VI rotor. Using the same modeling setup, the hybrid configuration demonstrates a systematic increase in peak power coefficient from 0.38 to 0.42 at a tip speed ratior &amp;lambda; = 5.41, reaching 0.448 at higher tip-speed ratios. Flow-field analysis reveals outward redistribution of tangential loading, a shift toward a more chordwise-distributed pressure response, delayed separation progression, and a more confined wake structure at elevated wind speeds. The results show that controlled outer-span hybridization within a benchmark rotor can enhance torque retention and aerodynamic stability without full-blade redesign.</p>
</abstract>
<counts><page-count count="25"/></counts>
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