Characterizing influence of transition to turbulence on the propulsive performance of underwater gliders
Characterizing influence of transition to turbulence on the propulsive performance of underwater gliders
Two models of underwater
gliders were tested in a wind tunnel, one corresponding to a legacy shape
commonly used in contemporary vehicles, the other being a scaled-down
version of a new design. Performance of the two vehicles was
characterised over a range of speeds and angles of attack. Particular
attention was paid to the effect of sharp features along the hulls of
the two vehicles and how they affect the observed flow regime. It has
been shown that the new design, which employs a bow shaped to encourage
natural laminar flow, benefits from a 10% reduction of parasitic drag
and 13%
increase in L/D when the hull surface is smooth. The legacy
glider, made up of a faired bow and a cylindrical hull, suffers from
laminar separation and up to 100% increase in induced drag if the flow
over its bow is prevented from transitioning to a turbulent state before
encountering adverse pressure gradient at lower Reynolds numbers. This
results in lowering of attainable speed at shallow glide path angles
while the associated parasitic drag reduction is demonstrated to
increase the maximum velocity of the glider when moving at glide slopes
above approximately 30.
autonomous underwater vehicle, experimental fluid dynamics, hydrodynamic performance, Underwater glider
1-8
Lidtke, Artur
5570c46b-09b5-4345-9f5c-7a5ed2a29ffc
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce
Downes, Jonathan
ebc0f09b-9d33-4815-bedf-bc77df59c822
Lidtke, Artur
5570c46b-09b5-4345-9f5c-7a5ed2a29ffc
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce
Downes, Jonathan
ebc0f09b-9d33-4815-bedf-bc77df59c822
Lidtke, Artur, Turnock, Stephen and Downes, Jonathan
(2019)
Characterizing influence of transition to turbulence on the propulsive performance of underwater gliders.
Journal of Ship Research, .
(doi:10.5957/JOSR.09180050).
Abstract
Two models of underwater
gliders were tested in a wind tunnel, one corresponding to a legacy shape
commonly used in contemporary vehicles, the other being a scaled-down
version of a new design. Performance of the two vehicles was
characterised over a range of speeds and angles of attack. Particular
attention was paid to the effect of sharp features along the hulls of
the two vehicles and how they affect the observed flow regime. It has
been shown that the new design, which employs a bow shaped to encourage
natural laminar flow, benefits from a 10% reduction of parasitic drag
and 13%
increase in L/D when the hull surface is smooth. The legacy
glider, made up of a faired bow and a cylindrical hull, suffers from
laminar separation and up to 100% increase in induced drag if the flow
over its bow is prevented from transitioning to a turbulent state before
encountering adverse pressure gradient at lower Reynolds numbers. This
results in lowering of attainable speed at shallow glide path angles
while the associated parasitic drag reduction is demonstrated to
increase the maximum velocity of the glider when moving at glide slopes
above approximately 30.
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Accepted/In Press date: 29 January 2019
e-pub ahead of print date: 21 February 2019
Keywords:
autonomous underwater vehicle, experimental fluid dynamics, hydrodynamic performance, Underwater glider
Identifiers
Local EPrints ID: 430450
URI: http://eprints.soton.ac.uk/id/eprint/430450
ISSN: 0022-4502
PURE UUID: afa5d4db-0755-42cd-bf4e-aaf0d4be2eb0
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Date deposited: 01 May 2019 16:30
Last modified: 16 Mar 2024 04:18
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