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Effects of periodic forcing on mixing in turbulent shear layers and wakes

Roberts, F. A. and Roshko, A. (1985) Effects of periodic forcing on mixing in turbulent shear layers and wakes. In: AIAA Shear Flow Control Conference, March 12-14, 1985, Boulder, CO.

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The effects of a periodic disturbance, applied to the one of the the free streams, on large-scale structure and mixing processes in chemically reacting shear layers and wakes were investigated over a range of Reynolds numbers above and below the mixing transition range. Two different methods were employed to measure the amount of chemical product and thus the extent of molecular-scale mixing. Absorption by reacted phenolphthalein provided cross-stream average product thickness and laser induced fluorescence intensity provided the product concentration distribution. These methods provided, in addition, effective flow visualization of the large-scale structures and of their response to the periodic forcing. The detailed effects of periodic forcing on distribution of mixing along a free shear layer are complex, but the predominant, overall effect is to increase mixing at low Reynolds number (in respect to the mixing transition) and to decrease it at high Reynolds number.

Item Type:Conference or Workshop Item (Paper)
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Additional Information:This paper is declared a work of the U.S. Government and therefore is in the public domain. This work was supported by the Office of Naval Research under Contract N00014-76-C-0260. Help and support by Professor Paul Dimotakis and Drs. Manooch Koochesfahani, Dan Nosenchuck and Dan Lang on this project is acknowledged.
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Office of Naval Research (ONR)N00014-76-C-0260
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AIAA Paper85-0570
Record Number:CaltechAUTHORS:20141210-133626177
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Official Citation:Effects of periodic forcing on mixing in turbulent shear layers and wakes A. ROSHKO, F. ROBERTS Shear Flow Control Conference, 1985, 10.2514/6.1985-570
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52558
Deposited By: George Porter
Deposited On:10 Dec 2014 22:04
Last Modified:10 Nov 2021 19:42

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