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The influence of free-stream turbulence on turbulent boundary layers with mild adverse pressure gradientsThe influence of near isotropic free-stream turbulence on the shape factors and skin friction coefficients of turbulent boundary layers is presented for the cases of zero and mild adverse pressure gradients. With free-stream turbulence, improved fluid mixing occurs in boundary layers with adverse pressure gradients relative to the zero pressure gradient condition, with the same free-stream turbulence intensity and length scale. Stronger boundary layers with lower shape factors occur as a result of a lower ratio of the integral scale of turbulence to the boundary layer thickness, and to vortex stretching of the turbulent eddies in the free-stream, both of which act to improve the transmission of momentum from the free-stream to the boundary layers.
Document ID
19890012674
Document Type
Contractor Report (CR)
Authors
Hoffmann, J. A. (California Polytechnic State Univ. San Luis Obispo, CA, United States)
Kassir, S. M. (California Polytechnic State Univ. San Luis Obispo, CA, United States)
Larwood, S. M. (California Polytechnic State Univ. San Luis Obispo, CA, United States)
Date Acquired
September 5, 2013
Publication Date
February 1, 1989
Subject Category
FLUID MECHANICS AND HEAT TRANSFER
Report/Patent Number
NASA-CR-177520
NAS 1.26:177520
Funding Number(s)
CONTRACT_GRANT: NCC2-450
PROJECT: RTOP 505-36-21
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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NameType 19890012674.pdf STI