Investigation on the aerodynamic performance of cycloidal rotors with active leading-edge morphing

Ferrier, Liam (2020) Investigation on the aerodynamic performance of cycloidal rotors with active leading-edge morphing. PhD thesis, University of Glasgow.

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Abstract

A cycloidal rotor is a novel form of propulsion system which has a geometrical design differing completely from the conventional screw propeller. The blades of a cycloidal rotor rotate about the horizontal axis of rotation. A key advantage of this rotor system is the instantaneous control of the net thrust vector, meaning that the thrust can be adjusted to any desired direction, perpendicular to the rotor’s horizontal axis of rotation. Few investigations have been conducted to assess the negative impact dynamic stall has on the cycloidal rotor’s performance characteristics. Dynamic stall is a complex phenomenon associated with unsteady aerofoil pitching motion that generates large hysteresis effects on the blade’s aerodynamic characteristics during the pitch cycle.

In this study, an investigation is conducted to assess the effect of active leading-edge morphing on alleviating the negative impact dynamic stall has on the aerofoil
aerodynamic characteristics as well as the cycloidal rotor performance characteristics. Computational studies are performed for a large-scale cycloidal rotor and for a single pitch-oscillating symmetric aerofoil operating at a large Reynolds number, Re greater than 1,000,000. Dynamic stall wind tunnel testing of a single NACA0015 aerofoil with an active leading-edge flap is also conducted to validate the effects of leading-edge morphing from the single pitch-oscillating aerofoil’s CFD model.

The main findings from this study showed that applying active leading-edge
morphing resulted in significant improvements of both the single aerofoil’s aerodynamic characteristics and the cycloidal rotor’s performance characteristics. The results from the CFD for the single pitch-oscillating aerofoil showed that the negative effects of dynamic stall were alleviated when applying active leading-edge morphing. The results from the cycloidal rotor CFD simulations showed that the effects of dynamic stall were alleviated which led to a reduction in the level of blade-wake interference. This led to a significant improvement in the cycloidal rotor performance characteristics, such as a 4-blade cycloidal rotor with active leading-edge morphing applied producing less power dissipation in comparison to a rigid 2-blade cycloidal rotor. The main findings from the experimental analysis showed that active leading-edge morphing reduced negative effects of dynamic stall such as the level of aerodynamic hysteresis, as well as improving the aerodynamic efficiency.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Aerodynamics, dynamic stall, cycloidal rotors, morphing, computation fluid dynamics, wind tunnel testing.
Subjects: T Technology > TL Motor vehicles. Aeronautics. Astronautics
Colleges/Schools: College of Science and Engineering > School of Engineering > Aerospace Sciences
Supervisor's Name: Vezza, Dr. Marco and Zare-Behtash, Dr. Hossein
Date of Award: 2020
Depositing User: Mr Liam Ferrier
Unique ID: glathesis:2020-81694
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 05 Oct 2020 08:52
Last Modified: 05 Oct 2020 08:52
URI: http://theses.gla.ac.uk/id/eprint/81694

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