On the limits of added-mass theory in separated flows and with varying initial conditions
On the limits of added-mass theory in separated flows and with varying initial conditions
It remains unclear to what extent inviscid added-mass theory accounts for the forces exerted on an accelerating body subjected to separated flow. In this study, reactant forces and velocity-field data are systematically acquired using experimental measurements and simulations of an accelerating circular flat plate. Cases accelerated from rest are compared to cases accelerated from a steady flow state. When the added-mass forces predicted by potential theory and the resistance forces associated with the instantaneous plate velocity are accounted for, the remaining (residual) forces comprise approximately 20% of the peak force, even at high accelerations. In addition, the computed residual forces during accelerations both from rest and steady-state cases yield good collapse with respect to one another, indicating that the total forces are not a strong function of the initial state of the wake. These results suggests that inviscid added-mass theory is inadequate to predict the full reactant force even in the ‘ideal’ condition of impulsive motion from rest.
Separated flows, Swimming/flying, Vortex dynamics
1-11
Fernando, John N.
992e5807-04e9-4074-b476-e64cf9b2a91d
Weymouth, Gabriel
b0c85fda-dfed-44da-8cc4-9e0cc88e2ca0
Rival, David E.
87169441-f569-46d8-8add-bbdbbdc70a01
February 2020
Fernando, John N.
992e5807-04e9-4074-b476-e64cf9b2a91d
Weymouth, Gabriel
b0c85fda-dfed-44da-8cc4-9e0cc88e2ca0
Rival, David E.
87169441-f569-46d8-8add-bbdbbdc70a01
Fernando, John N., Weymouth, Gabriel and Rival, David E.
(2020)
On the limits of added-mass theory in separated flows and with varying initial conditions.
Journal of Fluids and Structures, 93, , [102835].
(doi:10.1016/j.jfluidstructs.2019.102835).
Abstract
It remains unclear to what extent inviscid added-mass theory accounts for the forces exerted on an accelerating body subjected to separated flow. In this study, reactant forces and velocity-field data are systematically acquired using experimental measurements and simulations of an accelerating circular flat plate. Cases accelerated from rest are compared to cases accelerated from a steady flow state. When the added-mass forces predicted by potential theory and the resistance forces associated with the instantaneous plate velocity are accounted for, the remaining (residual) forces comprise approximately 20% of the peak force, even at high accelerations. In addition, the computed residual forces during accelerations both from rest and steady-state cases yield good collapse with respect to one another, indicating that the total forces are not a strong function of the initial state of the wake. These results suggests that inviscid added-mass theory is inadequate to predict the full reactant force even in the ‘ideal’ condition of impulsive motion from rest.
Text
Fernando2019
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Restricted to Repository staff only until 26 December 2020.
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Accepted/In Press date: 29 November 2019
e-pub ahead of print date: 26 December 2019
Published date: February 2020
Keywords:
Separated flows, Swimming/flying, Vortex dynamics
Identifiers
Local EPrints ID: 436274
URI: http://eprints.soton.ac.uk/id/eprint/436274
ISSN: 0889-9746
PURE UUID: 0754673c-9db4-40d3-9cdd-debe03116380
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Date deposited: 05 Dec 2019 17:30
Last modified: 08 Oct 2020 16:37
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Author:
John N. Fernando
Author:
David E. Rival
University divisions
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