The University of Southampton
University of Southampton Institutional Repository

On the effect of rapid area change in perching-like maneuvers

On the effect of rapid area change in perching-like maneuvers
On the effect of rapid area change in perching-like maneuvers
A perching bird is able to rapidly decelerate at a high angle of attack while maintaining lift and control. However, the underlying aerodynamic mechanism is poorly understood. We perform a study on a simultaneously decelerating and pitching airfoil section as a simple perching model. First, we use analytic arguments to establish the inertial non-circulatory force on a wing section, and its dependence on the shape change number, ? ??, the ratio between the rate of change of frontal dimension and the initial translational velocity. Next, we report that forces measured on a towed and pitched airfoil at Re = 22000, and forces from simulations at Re = 2000, are found to be well above non-circulatory predictions, exhibiting high lift and drag. Flow-field visualizations, both from Particle Image Velocimetry and simulations, reveal strong coherent vortical structures in the wake and near the body. At a higher shape change number, vortices in the wake convect more quickly than at a lower shape change number, generating higher drag. Additionally, separation of the LEV and positive vorticity near the body is reduced at a higher shape change number, increasing lift. Thus wake manipulation through rapid area change provides a means through which a perching bird can maintain high lift and drag simultaneously while slowing to a controlled stop.
978-1-62410-288-2
Polet, Delyle
cf18655f-044e-44f2-ab2b-a3222f4914d1
Christensen, Tyler
2038b771-c240-4812-98a6-a4c37f1ddb01
Rival, David
a2e24ff6-d135-4c51-ac7a-7c8877a18f5d
Weymouth, Gabriel
b0c85fda-dfed-44da-8cc4-9e0cc88e2ca0
Polet, Delyle
cf18655f-044e-44f2-ab2b-a3222f4914d1
Christensen, Tyler
2038b771-c240-4812-98a6-a4c37f1ddb01
Rival, David
a2e24ff6-d135-4c51-ac7a-7c8877a18f5d
Weymouth, Gabriel
b0c85fda-dfed-44da-8cc4-9e0cc88e2ca0

Polet, Delyle, Christensen, Tyler, Rival, David and Weymouth, Gabriel (2014) On the effect of rapid area change in perching-like maneuvers. 32nd AIAA Applied Aerodynamics Conference, United States. 16 - 20 Jun 2014. (doi:10.2514/6.2014-2836).

Record type: Conference or Workshop Item (Paper)

Abstract

A perching bird is able to rapidly decelerate at a high angle of attack while maintaining lift and control. However, the underlying aerodynamic mechanism is poorly understood. We perform a study on a simultaneously decelerating and pitching airfoil section as a simple perching model. First, we use analytic arguments to establish the inertial non-circulatory force on a wing section, and its dependence on the shape change number, ? ??, the ratio between the rate of change of frontal dimension and the initial translational velocity. Next, we report that forces measured on a towed and pitched airfoil at Re = 22000, and forces from simulations at Re = 2000, are found to be well above non-circulatory predictions, exhibiting high lift and drag. Flow-field visualizations, both from Particle Image Velocimetry and simulations, reveal strong coherent vortical structures in the wake and near the body. At a higher shape change number, vortices in the wake convect more quickly than at a lower shape change number, generating higher drag. Additionally, separation of the LEV and positive vorticity near the body is reduced at a higher shape change number, increasing lift. Thus wake manipulation through rapid area change provides a means through which a perching bird can maintain high lift and drag simultaneously while slowing to a controlled stop.

Text
AIAA conference paper final.pdf - Author's Original
Download (2MB)

More information

Published date: 16 June 2014
Venue - Dates: 32nd AIAA Applied Aerodynamics Conference, United States, 2014-06-16 - 2014-06-20
Organisations: Faculty of Engineering and the Environment

Identifiers

Local EPrints ID: 367714
URI: http://eprints.soton.ac.uk/id/eprint/367714
ISBN: 978-1-62410-288-2
PURE UUID: c29e5913-e2ab-4f1f-b15c-44214afe7d0f
ORCID for Gabriel Weymouth: ORCID iD orcid.org/0000-0001-5080-5016

Catalogue record

Date deposited: 06 Aug 2014 10:27
Last modified: 31 Jul 2019 00:33

Export record

Altmetrics

Contributors

Author: Delyle Polet
Author: Tyler Christensen
Author: David Rival

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×