Unsteady slot suction from a high-Reynolds-number cross-flow
Unsteady slot suction from a high-Reynolds-number cross-flow
The problem of unsteady suction from a high-Reynolds-number cross-flow into a slot is considered in the case where the suction is driven by a time-dependent slot pressure. The model uses linearised asymptotics based on a small parameter that defines the suction strength. An integro differential equation is derived for the mass flow into the slot and this is solved for various time-dependent slot pressures of practical interest. Closed-form expressions are also found for the shape of the shear layer dividing the external flow from the fluid in the slot. For a step function change in the slot pressure, a non-monotonic decay to the steady solution is observed, and for an oscillatory slot pressure there is a phase lag between the slot pressure and the mass flow. For rapidly changing slot pressures it is shown that slot injection can occur, even when the slot pressure remains below the free-stream pressure.
suction, injection, film cooling, hilbert transforms, thin aerofoil theory
293-310
Lattimer, T.R.B.
dae29958-2dfc-4a4a-9ede-b30311e42e1a
Fitt, A.D.
51b348d7-b553-43ac-83f2-3adbea3d69ab
1998
Lattimer, T.R.B.
dae29958-2dfc-4a4a-9ede-b30311e42e1a
Fitt, A.D.
51b348d7-b553-43ac-83f2-3adbea3d69ab
Lattimer, T.R.B. and Fitt, A.D.
(1998)
Unsteady slot suction from a high-Reynolds-number cross-flow.
Journal of Engineering Mathematics, 33 (3), .
(doi:10.1023/A:1004315008820).
Abstract
The problem of unsteady suction from a high-Reynolds-number cross-flow into a slot is considered in the case where the suction is driven by a time-dependent slot pressure. The model uses linearised asymptotics based on a small parameter that defines the suction strength. An integro differential equation is derived for the mass flow into the slot and this is solved for various time-dependent slot pressures of practical interest. Closed-form expressions are also found for the shape of the shear layer dividing the external flow from the fluid in the slot. For a step function change in the slot pressure, a non-monotonic decay to the steady solution is observed, and for an oscillatory slot pressure there is a phase lag between the slot pressure and the mass flow. For rapidly changing slot pressures it is shown that slot injection can occur, even when the slot pressure remains below the free-stream pressure.
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Published date: 1998
Keywords:
suction, injection, film cooling, hilbert transforms, thin aerofoil theory
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Local EPrints ID: 29118
URI: http://eprints.soton.ac.uk/id/eprint/29118
ISSN: 0022-0833
PURE UUID: 77744a03-5a53-483c-8f66-aa91466e356a
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Date deposited: 22 Dec 2006
Last modified: 15 Mar 2024 07:29
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Author:
T.R.B. Lattimer
Author:
A.D. Fitt
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