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Progress towards modelling unsteady forces using a drift-volume approach

Progress towards modelling unsteady forces using a drift-volume approach
Progress towards modelling unsteady forces using a drift-volume approach
Classical potential flow added mass theory does not appear to account for all the force experienced by an accelerating body, especially in separated flow. The drift-volume method has shown good agreement with experiment for a highly accelerated case [1], and has been extended in this study to a kinematics-based force model. An optical towing tank facility is used to measure the forces and flow around a circular flat plate normal to the free stream fora range of acceleration moduli. Lagrangian particle tracks were produced using the Eulerian vector-fields and synthetic particle tracking velocimetry. Compared to classical theory, when the “added mass" is determined using the drift volume approach, an additional rate-of-change of added mass term appears, and is shown to be a significant component of the total force. In addition, the particle tracks revealed that the vortex ring development behind the flat plate made up a remarkable portion of the drift volume. From this observation a model for the unsteady forces via drift volume development is proposed, using a conservation of mass scheme[2]. An enstrophy-history method as described by Rosiet al.[3] is used to determine the role of entrainment in the vortex ring growth, incorporated into the unsteady force model.
Aerospace Research Central
Galler, Josh
25350c0b-201c-4544-b7a8-09ab2c57404e
Weymouth, Gabriel
b0c85fda-dfed-44da-8cc4-9e0cc88e2ca0
Rival, David
a2e24ff6-d135-4c51-ac7a-7c8877a18f5d
Galler, Josh
25350c0b-201c-4544-b7a8-09ab2c57404e
Weymouth, Gabriel
b0c85fda-dfed-44da-8cc4-9e0cc88e2ca0
Rival, David
a2e24ff6-d135-4c51-ac7a-7c8877a18f5d

Galler, Josh, Weymouth, Gabriel and Rival, David (2019) Progress towards modelling unsteady forces using a drift-volume approach. In AIAA SciTech 2019 Forum. Aerospace Research Central.. (doi:10.2514/6.2019-1147).

Record type: Conference or Workshop Item (Paper)

Abstract

Classical potential flow added mass theory does not appear to account for all the force experienced by an accelerating body, especially in separated flow. The drift-volume method has shown good agreement with experiment for a highly accelerated case [1], and has been extended in this study to a kinematics-based force model. An optical towing tank facility is used to measure the forces and flow around a circular flat plate normal to the free stream fora range of acceleration moduli. Lagrangian particle tracks were produced using the Eulerian vector-fields and synthetic particle tracking velocimetry. Compared to classical theory, when the “added mass" is determined using the drift volume approach, an additional rate-of-change of added mass term appears, and is shown to be a significant component of the total force. In addition, the particle tracks revealed that the vortex ring development behind the flat plate made up a remarkable portion of the drift volume. From this observation a model for the unsteady forces via drift volume development is proposed, using a conservation of mass scheme[2]. An enstrophy-history method as described by Rosiet al.[3] is used to determine the role of entrainment in the vortex ring growth, incorporated into the unsteady force model.

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More information

e-pub ahead of print date: 6 January 2019
Published date: 2019

Identifiers

Local EPrints ID: 428111
URI: https://eprints.soton.ac.uk/id/eprint/428111
PURE UUID: 6d5e6948-8164-4837-928e-28cf4e422505
ORCID for Gabriel Weymouth: ORCID iD orcid.org/0000-0001-5080-5016

Catalogue record

Date deposited: 11 Feb 2019 17:30
Last modified: 26 Jul 2019 00:31

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