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On the spreading of turbulent spots in nonisothermal laminar boundary layers under the influence of favourable pressure gradients

On the spreading of turbulent spots in nonisothermal laminar boundary layers under the influence of favourable pressure gradients
On the spreading of turbulent spots in nonisothermal laminar boundary layers under the influence of favourable pressure gradients
A comprehensive experimental investigation of the aerodynamic and thermal spreading of turbulent spots in favourable pressure gradients. Measurements were taken with shear stress and temperature sensitive paint, surface hot films, and hot wires on a flat plate in a low speed test facility. The turbulent spots were triggered with a frequency of 120 Hz at a location with a momentum thickness Reynolds-number of 400. The thermal spread was measured using a heated plate.

The spreading angle of turbulence was found to depend on the acceleration parameter K = (n/U*U).dU/dx

AC --- 0 0.25E-6 1.00E-6

Aerodynamic deg 6.9 5.9 3.3

Thermal deg 6.8 4.8 2.5

Spreading is slower in accelerating flow and the momentum boundary layer establishes the turbulent flow state faster than the thermal boundary layer. The measured spreading angles in zero pressure gradient are lower than the 10 deg identified in other experiments. A comparison between surface hot film and hot wire measurements away from the wall indicate that this is due to a lateral "overhang" of the turbulent regime which spreads slower close to the wall than some distance form it.
0791836061
571-579
American Society Of Mechanical Engineers (ASME)
Zhong, S.
e52648be-29fe-4597-bece-e28eec163b8b
Chong, T.P.
df7a2c0c-9f56-44dd-b668-8ef83d3e2c0d
Hodson, H.P.
33764088-9890-4258-8b49-70ebcd71d488
Zhong, S.
e52648be-29fe-4597-bece-e28eec163b8b
Chong, T.P.
df7a2c0c-9f56-44dd-b668-8ef83d3e2c0d
Hodson, H.P.
33764088-9890-4258-8b49-70ebcd71d488

Zhong, S., Chong, T.P. and Hodson, H.P. (2002) On the spreading of turbulent spots in nonisothermal laminar boundary layers under the influence of favourable pressure gradients. In Proceedings of the Asme Turbo Expo 2002. American Society Of Mechanical Engineers (ASME). pp. 571-579 .

Record type: Conference or Workshop Item (Paper)

Abstract

A comprehensive experimental investigation of the aerodynamic and thermal spreading of turbulent spots in favourable pressure gradients. Measurements were taken with shear stress and temperature sensitive paint, surface hot films, and hot wires on a flat plate in a low speed test facility. The turbulent spots were triggered with a frequency of 120 Hz at a location with a momentum thickness Reynolds-number of 400. The thermal spread was measured using a heated plate.

The spreading angle of turbulence was found to depend on the acceleration parameter K = (n/U*U).dU/dx

AC --- 0 0.25E-6 1.00E-6

Aerodynamic deg 6.9 5.9 3.3

Thermal deg 6.8 4.8 2.5

Spreading is slower in accelerating flow and the momentum boundary layer establishes the turbulent flow state faster than the thermal boundary layer. The measured spreading angles in zero pressure gradient are lower than the 10 deg identified in other experiments. A comparison between surface hot film and hot wire measurements away from the wall indicate that this is due to a lateral "overhang" of the turbulent regime which spreads slower close to the wall than some distance form it.

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More information

Published date: 2002
Venue - Dates: ASME International Gas Turbine Conference Turbo Expo 2002,, Amsterdam, The Netherlands, 2002-06-02 - 2002-06-05

Identifiers

Local EPrints ID: 10266
URI: http://eprints.soton.ac.uk/id/eprint/10266
ISBN: 0791836061
PURE UUID: 5e7ad671-1e25-472b-a25e-b02001ca9f27

Catalogue record

Date deposited: 11 Jan 2005
Last modified: 08 Jan 2022 15:45

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Contributors

Author: S. Zhong
Author: T.P. Chong
Author: H.P. Hodson

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