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http://dx.doi.org/10.5139/JKSAS.2013.41.10.761

A Numerical Investigation of the Main Rotor Tip-vortex and Counter-rotating Vortex during Hovering Flight  

Jun, Jonghyuk (Division of Aerospace Engineering, Korea Advanced Institute of Science and Technology(KAIST))
Chung, In Jae (Agency for Defense Development(ADD))
Lee, Duck Joo (Division of Aerospace Engineering, Korea Advanced Institute of Science and Technology(KAIST))
Publication Information
Journal of the Korean Society for Aeronautical & Space Sciences / v.41, no.10, 2013 , pp. 761-769 More about this Journal
Abstract
Effects of helicopter wakes on helicopter aerodynamics are serious, but the wake configuration is very complicated and hard to predict. The purpose of this study is the detailed observation of wake using numerical methods. Vortex lattice method and freewake method are used to track the vortices in the wake. In this paper, the wake configuration is observed during hovering flight. In the case of hovering flight at the moderate thrust level, besides tip vortex, counter-rotating vortex can be observed at the inboard part of blade. When the vortices move downward, tip vortex and counter-rotating vortex get close and influence to each other. Therefore, vortices are highly distorted due to their own instability.
Keywords
Hovering; Tip Vortex; Counter-rotating Vortex; Wake Configuration;
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1 Na, S.W., Ryu, K.W. and Lee, D.J., "Comparison of the Helicopter Wake Modeling in Hovering Motion," The Korean Society for Aeronautical and Space Sciences Autumn Conference, 1992.11, pp.307-311.
2 Jain, R., Conlisk, A.T., "Interaction of Tip-Vortices in the Wake of a Two-Bladed Rotor in Axial Flight," American Helicopter Society 54th Annual Forum, Washington, DC, May 20-22, 1998.
3 Jung, K.H., Na, S.U., Jeon, W.H., Lee, D.J., "Numerical Prediction of Rotor Tip-Vortex Roll-Up in Axial Flights by Using a Time-Marching Free-Wake Method," KSAS International Journal Volume.1 Number.1, 2000.5, 1-12
4 Widnall, S.E., "The Stability of a Helical Vortex Filament," Journal of Fluid Mechanics, Vol.54, No.4, 1972, pp.641-663.   DOI
5 Crow, S.C., "Stability theory for a pair of trailing vortices," AIAA Journal, vol. 8, issue 12, pp. 2172-2179. 1970.   DOI
6 Johnson, W.J., "Helicopter Theory," Princeton University Press, 1980.
7 Vatistas, G. H., Kozel, V., and Mih, W. C., "A Simpler Model for Concentrated Vortices," Experiments in Fluids, Vol. 11, No. 1, 1991.
8 Ryu, K.W. and Lee, D.J., "Sound Radiation from Elliptic Vortex Rings: Evolution and Interaction," Journal of Sound and Vibration, 200, (3), 1997.
9 Lorber, P. F., Stauter, R. C., Landgrebe, A.J., "A Comprehensive Hover Test of the Airloads and Airflow of an Extensively Instrumented Model Helicopter Rotor," American Helicopter Society 45th Annual Forum, Boston, MA, May 1989.
10 Barker, James T., "United States Army Aviation Safety," 1st Asian/Australian Rotorcraft Forum and Exhibition, Feb. 12-15, 2012, Busan, Korea.
11 Landgrebe, "The Wake Geometry of a Hovering Helicopter Rotor and Its Influence on Rotor Performance," 28th Annual National Forum of the American Helicopter Society, May 1972.
12 Caradonna, F.X., Hedley, E., Silva, M., Huang,S., Komerath, N., Reddy, U.,Mahalingam, R., Funk, R., Ames, R., Darden, L., Villareal, L., Gregory, J., and Wong, O., "An Experimental Study of a Rotor in Axial Flight," AHS Specialists' Meeting on Aerodynamics and Aeroacoustics, AHS International, Alexandria, VA, Oct. 1997.
13 Kim, J.M., Komerath, N.M., Liou, S.G., "Vorticity Concentration at the Edge of the Inboard Vortex Sheet," Journal of the American Helicopter Society, Volume 39, Number 2, 1 April 1994 , pp. 30-34(5)   DOI
14 Ghee T., Berry JD., Zori LAJ., Elliott JW., "Wake geometry measurements and analytical calculations on a small-scale rotor model," NASA TP 3584. 1995.