Author ORCID Identifier

0009-0005-1492-5025

Date of Award

17-8-2025

Document Type

Thesis

School

School of Mechanical Engineering

Programme

Ph.D.-Doctoral of Philosophy

First Advisor

Dr.S.Nadaraja Pillai

Keywords

Vertical Axis Wind Turbine (VAWT), Dynamic Stall, Leading-Edge Protuberance (LEP), Unsteady Aerodynamics, Wind Tunnel Experiments

Abstract

The growing wind energy sector and demand for renewable energy have led to increased wind turbine installations and alternatives to horizontal-axis wind turbines, such as small-scale turbines. The trends are shifting toward the use of readily available energy alone or with sustainable sources, such as solar or geothermal energy. The creation of self-sustaining energy capture and urban installations for developing smart grids is in great demand. A vertical-axis wind turbine is one such alternative. The performance of vertical-axis wind turbines is affected by drag, dynamic stalls, and vibrations from turbulent flow. Time-varying flow causes structural instabilities, leading to the vibration of the VAWT and structural support.

Unsteady flow separation over turbine blades due to rapid angle-of-attack changes with leading-edge vortex formation reduces aerodynamic efficiency. Researchers have studied the static aerodynamic characteristics of modified leading-edge protuberances (LEPs) at varying wind regimes and LEP blades on rotating VAWTs. The influence of passive flow control devices inspired by humpback whales on the structural integrity of VAWTs remains unexplored. Wind tunnel experiments were performed on the airfoil profile of straight blades for vertical-axis wind turbine applications. The experiment used a free-stream velocity of 30 m/s, corresponding to a Reynolds number of 2.3×105.

Testing was performed on baseline and modified airfoil profiles at 0-45° angles in 5° intervals. Static and dynamic stall characteristics were studied using surface-pressure measurements. The modified VAWT with and without LEP was simulated in ANSYS using DES, and the aerodynamic characteristics and flow patterns were analyzed. Wind tunnel testing examined the vibrational characteristics of wind and operational loads at varying speeds, pitch angles, and solidities. Triaxial accelerometer data were analyzed to understand the vibration reduction.

Download

Share

COinS