A numerical study on bio-inspired aerofoils oscillating in tandem

Previous study by Flint et al. [1] investigated the flow behaviour of a single bio-inspired corrugated aerofoil in oscillatory pitching motion. In that paper, the effects of varying frequencies and amplitudes of oscillation were investigated. As a dragonfly has two pairs of wings, a natural progress...

Full description

Saved in:
Bibliographic Details
Main Author: Chua, Kok Nam
Other Authors: New Tze How Daniel
Format: Final Year Project
Language:English
Published: 2018
Subjects:
Online Access:http://hdl.handle.net/10356/75100
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-75100
record_format dspace
spelling sg-ntu-dr.10356-751002023-03-04T18:22:16Z A numerical study on bio-inspired aerofoils oscillating in tandem Chua, Kok Nam New Tze How Daniel School of Mechanical and Aerospace Engineering DRNTU::Engineering::Aeronautical engineering::Aerodynamics Previous study by Flint et al. [1] investigated the flow behaviour of a single bio-inspired corrugated aerofoil in oscillatory pitching motion. In that paper, the effects of varying frequencies and amplitudes of oscillation were investigated. As a dragonfly has two pairs of wings, a natural progression would be to expand on these findings into investigating the effects and flow interactions between two tandemly-positioned aerofoils in synchronised pitching motion. This study aims to establish a better understanding of the inter-wings flow interactions, and how changes in the oscillation frequencies and amplitudes could affect the lifting and thrust performance of both the fore- and aft-aerofoils. Two-dimensional flow simulation at Re=14,000 was carried out on five different cases of motion, by first varying the oscillation frequency, then the oscillation amplitude. It was observed that through the aft-aerofoil’s interaction with fore-aerofoil’s wake, the aft-aerofoil consistently showed an increase in the resultant maximum lift in both the positive and negative directions. The amount of augmentation however was found to be unsymmetrical, with a larger amount of improvement observed towards the negative lifting direction. As a result, when considering the aft-aerofoil’s mean lifting performance through one full oscillation, it was found to have performed worse than the fore-aerofoil. The thrust performance for the aft-aerofoil was found to largely depend on the specific vortex dynamics of each motion case, and no obvious trend was observed as frequency and amplitude was varied. It was also observed that positive thrust was only produced at cases with large rates of aerofoil rotation, where St>0.4, consistent with the findings of the single-aerofoil study. At zero phase difference, the resultant vortex dynamics had significant influence over the lifting performance of the aft-aerofoil, but with little influence over its thrust performance. Bachelor of Engineering (Aerospace Engineering) 2018-05-28T05:32:06Z 2018-05-28T05:32:06Z 2018 Final Year Project (FYP) http://hdl.handle.net/10356/75100 en Nanyang Technological University 76 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Aeronautical engineering::Aerodynamics
spellingShingle DRNTU::Engineering::Aeronautical engineering::Aerodynamics
Chua, Kok Nam
A numerical study on bio-inspired aerofoils oscillating in tandem
description Previous study by Flint et al. [1] investigated the flow behaviour of a single bio-inspired corrugated aerofoil in oscillatory pitching motion. In that paper, the effects of varying frequencies and amplitudes of oscillation were investigated. As a dragonfly has two pairs of wings, a natural progression would be to expand on these findings into investigating the effects and flow interactions between two tandemly-positioned aerofoils in synchronised pitching motion. This study aims to establish a better understanding of the inter-wings flow interactions, and how changes in the oscillation frequencies and amplitudes could affect the lifting and thrust performance of both the fore- and aft-aerofoils. Two-dimensional flow simulation at Re=14,000 was carried out on five different cases of motion, by first varying the oscillation frequency, then the oscillation amplitude. It was observed that through the aft-aerofoil’s interaction with fore-aerofoil’s wake, the aft-aerofoil consistently showed an increase in the resultant maximum lift in both the positive and negative directions. The amount of augmentation however was found to be unsymmetrical, with a larger amount of improvement observed towards the negative lifting direction. As a result, when considering the aft-aerofoil’s mean lifting performance through one full oscillation, it was found to have performed worse than the fore-aerofoil. The thrust performance for the aft-aerofoil was found to largely depend on the specific vortex dynamics of each motion case, and no obvious trend was observed as frequency and amplitude was varied. It was also observed that positive thrust was only produced at cases with large rates of aerofoil rotation, where St>0.4, consistent with the findings of the single-aerofoil study. At zero phase difference, the resultant vortex dynamics had significant influence over the lifting performance of the aft-aerofoil, but with little influence over its thrust performance.
author2 New Tze How Daniel
author_facet New Tze How Daniel
Chua, Kok Nam
format Final Year Project
author Chua, Kok Nam
author_sort Chua, Kok Nam
title A numerical study on bio-inspired aerofoils oscillating in tandem
title_short A numerical study on bio-inspired aerofoils oscillating in tandem
title_full A numerical study on bio-inspired aerofoils oscillating in tandem
title_fullStr A numerical study on bio-inspired aerofoils oscillating in tandem
title_full_unstemmed A numerical study on bio-inspired aerofoils oscillating in tandem
title_sort numerical study on bio-inspired aerofoils oscillating in tandem
publishDate 2018
url http://hdl.handle.net/10356/75100
_version_ 1759858202244022272