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Technical Brief

Localization of Flow Separation and Transition Over a Pitching NACA0012 Airfoil at Transitional Reynolds Numbers Using Hot-Films

[+] Author and Article Information
Allison Poels, Daniel Rudmin, Dominique Poirel

Department of Mechanical and Aerospace Engineering,
Royal Military College of Canada,
Kingston, ON K7K 7B4, Canada

Azemi Benaissa

Department of Mechanical and Aerospace Engineering,
Royal Military College of Canada,
Kingston, ON K7K 7B4, Canada
e-mail: benaissa-a@rmc.ca

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received July 10, 2014; final manuscript received July 6, 2015; published online August 6, 2015. Assoc. Editor: Feng Liu.

J. Fluids Eng 137(12), 124501 (Aug 06, 2015) (6 pages) Paper No: FE-14-1371; doi: 10.1115/1.4031008 History: Received July 10, 2014

Separation and transition of flow over a pitching airfoil at transitional Reynolds Number are analyzed experimentally. The method is based on a windowed correlation between hot-film sensor signals taken simultaneously or synchronized based on the airfoil pitch angle. A comparison with large eddy simulation (LES) simulation obtained in the same conditions is presented and discussed. Our results agree very well with the LES data for the separation location during the pitch-up. For the pitch-down, the results show differences with the LES. However, when the LES data are analyzed with the same correlation technique, the results are in a better agreement.

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References

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Figures

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Fig. 2

Wake of the driven airfoil wake (a) and free airfoil wake (b)

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Fig. 3

Phase-matched hot-film signals

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Fig. 4

Windowed cross-correlations

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Fig. 5

Correlation process

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Fig. 6

Hot-film correlations for Re = 820,000

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Fig. 7

Experimental cycle-averaged correlations at Re = 82,000

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Fig. 8

Average incidence of separation and transition for each chord position for Re = 62,000

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Fig. 9

Average incidence of separation and transition for each chord position for Re = 113,000

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Fig. 10

Average incidence of separation and transition for each chord position for Re = 82,000

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Fig. 11

Correlation coefficients from LES shear stress [15]

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