Experimental Investigation of Bio-Inspired Serrated Vortex Generators for Performance Improvement of an H-Rotor Darrieus Vertical Axis Wind Turbine

Oct 22, 2026

Vertical-axis wind turbines (VAWTs) face challenges achieving high aerodynamic performance, especially in low-wind-speed urban environments where flow separation and dynamic stall restrict energy extraction. This study evaluates an H-rotor Darrieus VAWT fitted with bio-inspired serrated vortex generators (SVGs) as passive flow control, inspired by owl-feather serrations. Wind-tunnel tests at Reynolds number 40,000 compare baseline and SVG-modified NACA 4415 blades, followed by outdoor turbine evaluation with statistical process control. Results show higher maximum lift (~6%) and mean power output (+44%), but also increased drag (~30%) and reduced lift-to-drag ratio (-18%), indicating optimization needs.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages24

Reading Time1 h 0 min

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Abstract

Keywords

I. Introduction

Journal Pre-proof Experimental Investigation of Bio-Inspired Serrated Vortex Generators for Performance Improvement of an H-Rotor Darrieus Vertical Axis Wind Turbine Nur Faraihan Zulkefli, Muhammad Deni Danial Azahar, Nurhayati Mohd Nur, Mohammad Arafat PII: S2950-6018(26)00057-6 DOI: [https://doi.org/10.1016/j.awe.2026.100155](https://doi.org/10.1016/j.awe.2026.100155) [Reference: AWE100155](Reference: AWE100155) To appear in: Advances in WindEngineering Received date: 9 July 2026 Revised date: 11 August 2026 Accepted date: 18 August 2026 Please cite this article as: Nur Faraihan Zulkefli, Muhammad Deni Danial Azahar, Nurhayati Mohd Nur and Mohammad Arafat, Experimental Investigation of Bio-Inspired Serrated Vortex Generators for Performance Improvement of an H-Rotor Darrieus Vertical Axis Wind Turbine, Advances in WindEngineering,(2026) doi:[https://doi.org/10.1016/j.awe.2026.100155](https://doi.org/10.1016/j.awe.2026.100155) This is a PDF of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability. This version will undergo additional copyediting, typesetting and review before it is published in its final form. As such, this version is no longer the Accepted Manuscript, but it is not yet the definitive Version of Record; we are providing this early version to give early visibility of the article. Please note that Elsevier’s sharing policy for the Published Journal Article applies to this version, see: [https://www.elsevier.com/about/policies-and-standards/sharing\#4-published](https://www.elsevier.com/about/policies-and-standards/sharing#4-published)journal-article. Please also note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Experimental Investigation of Bio-Inspired Serrated Vortex Generators for Performance Improvement of an H Rotor Darrieus Vertical Axis Wind Turbine Nur Faraihan Zulkefli 1, **, Muhammad Deni Danial Azahar1, Nurhayati Mohd Nur 1, Mohammad Arafat 1, ** 1Department of Aerospace, Malaysian Institute of Aviation Technology (MIAT), Universiti Kuala Lumpur, 43800 Dengkil, Selangor, Malaysia ABSTRACT Vertical-axis wind turbines (VAWTs) face challenges in achieving high aerodynamic performance, particularly in lowwind-speed urban environments where flow separation and dynamic stall can limit energy extraction. This study investigates the performance of an H-rotor Darrieus VAWT equipped with bio-inspired serrated vortex generators (SVGs) as a passive flow-control strategy. Inspired by owl-feather serrations, the SVGs were attached to NACA 4415 airfoil blades at 30% of the chord from the leading edge. Wind-tunnel experiments were conducted at a Reynolds number of 40,000 to characterize the aerodynamic performance of the baseline and SVG-equipped airfoils. The modified blades were subsequently installed on a 1-m-tall H-rotor Darrieus VAWT and evaluated under naturally varying outdoor wind conditions using statistical process control. The SVG-equipped airfoil achieved approximately 6% higher maximum lift coefficient than the baseline configuration, although it also exhibited an approximately 30% increase in drag coefficient and an 18% reduction in lift-to-drag ratio. Under outdoor operating conditions, the SVG-equipped turbine exhibited higher mean values of blade rotational speed, wind power, power output, torque coefficient, and speed ratio than the baseline configuration. In particular, the mean power output increased from 2.69 W to 3.87 W, corresponding to an increase of approximately 44%. The corresponding range increased from 5.77 W to 6.60 W, or approximately 14%, indicating that the higher mean performance was accompanied by increased variability under the naturally fluctuating outdoor conditions. Supporting CFD analysis provided qualitative insight into the flow mechanism, showin

FAQs

What problem do vertical-axis wind turbines face in low-wind-speed urban environments?

They struggle to achieve high aerodynamic performance because flow separation and dynamic stall limit energy extraction.

How were the bio-inspired serrated vortex generators applied in the study?

SVGs inspired by owl-feather serrations were attached to NACA 4415 airfoil blades at 30% chord from the leading edge.

What were the main performance changes when using SVGs?

The SVG-equipped configuration increased maximum lift coefficient by about 6% and raised mean power output from 2.69 W to 3.87 W (~44%), while drag increased about 30% and lift-to-drag ratio decreased about 18%.

Oct 22, 2026

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