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Modelling of static aerodynamics of helicopter underslung loads

Published online by Cambridge University Press:  27 January 2016

D. I. Greenwell
D. I. Greenwell*
Affiliation:
Centre for Aeronautics, City University, London, UK
*
d.greenwell@city.ac.uk
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Abstract

The complex aerodynamics of rectangular underslung helicopter loads can lead to severe stability problems, but are difficult to represent in flight dynamics models. Current models for box aerodynamics are highly unsatisfactory, being entirely empirical and requiring large amounts of experimental data to generate. This paper presents a new modelling approach, which takes account of the bluff-body nature of the flow, where loads are dominated by normal pressure forces. Existing experimental data is recast in body-axes form, with α and β replaced by velocity components perpendicular and parallel to the box faces. Force and moment data for a wide range of boxes then collapse onto a set of simple generic characteristics, with features that can be related directly to the underlying flow physics. Modelling of container aerodynamics is greatly simplified, and allowance for effects of turbulence, Reynolds Number, wind tunnel interference and geometry modifications becomes possible.

Information

Type
Research Article
Information
The Aeronautical Journal , Volume 115 , Issue 1166 , April 2011 , pp. 201 - 219
Copyright
Copyright © Royal Aeronautical Society 2011 

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References

1. Matheson, N. The stability of portable bridges carried on slings beneath helicopters, aerodynamics Report 154, DSTO, January 1980.Google Scholar
2. Sheldon, D.F. and Pryor, J. Study in depth of a single point and two point lateral and tandem suspension of rectangular box loads, Technical Note AM/38, Royal Military College of Science, 1973.Google Scholar
3. Stuckey, R.A. Mathematical modelling of helicopter slung-load systems, DSTO–TR–1257, December 2001.Google Scholar
4. Cicolani, L.S. and Ehlers, G.E. Modelling and simulation of a helicopter slung load stabilization device, American Helicopter Society 58th Annual Forum, Montreal, Canada, June 2002.Google Scholar
5. Pavel, M.D. Mathematical modelling of tandem helicopters with external sling loads for piloted simulations, AIAA-2006-6617, AIAA Modelling & Simulation Technologies Conference, Hilton Head, August 2007.Google Scholar
6. Kendrick, S. and Walker, D.J. The modelling, simulation and control of helicopters operating with external loads, 62nd American Helicopter Society Annual Forum, Phoenix, US, May 2006.Google Scholar
7. Bisgaard, M., Bendtsen, J.D. and La Cour-Harbo, A. Modeling of generic slung load system, J Guidance, Control, and Dynamics, March–April 2009, 32, (2), pp 573–585.Google Scholar
8. Duque, E.P.N. ET AL, Reynolds-averaged Navier-Stokes simulations of helicopter slung loads, AHS International 4th Decennial Specialists’ Conference on Aeromechanics, San Francisco, USA, January 2004.Google Scholar
9. Cicolani, L. and Kanning, G. A comprehensive estimate of the static aerodynamic forces and moments of the 8- by 8- by 20-Foot Cargo Container, NASA TM 89433, May 1987.Google Scholar
10. ESDU, Fluid forces, pressures and moments on rectangular blocks, ESDU datasheet 71016, November 1978.Google Scholar
11. Simpson, A. and Flower, J.W. Unsteady aerodynamics of oscillating containers and application to the problem of dynamic stability of helicopter underslung loads, paper 13 in AGARD CP-235 Dynamic Stability Parameters, November 1978.Google Scholar
12. Poli, C. and Cromack, D. Dynamics of slung bodies using a singlepoint suspension system, J Aircr, February 1973, 10, (2), pp 80–86.Google Scholar
13. Shaughnessy, J.D., Deaux, T.N. and Yenni, K.R. Development and validation of a piloted simulation of a helicopter and external slung load, NASA TP-1285, January 1979.Google Scholar
14. Weber, J.M., Liu, T.Y. and Chung, W. A Mathematical simulation model of the CH-47B helicopter, NASA TM-84351, August 1984 Google Scholar
15. Feaster, L., Poli, C. and Kirchoff, R. Dynamics of a slung load, J Aircr, February 1977, 14, (2), pp 115–121.Google Scholar
16. Ronen, T. Dynamics of a Helicopter with a Sling Load, PhD. Thesis, Dept. of Aeronautics and Astronautics, Stanford University, USA, August 1985 (also AIAA-86-2288).Google Scholar
17. Cicolani, L.S., Da Silva, J.G.A., Duque, E.P.N. and Tischler, M.B. Unsteady aerodynamic model of a cargo container for slung-load simulation, Aeronaut J, July 2004, 108, (1085), pp 357–368.Google Scholar
18. Norberg, C. Flow around rectangular cylinders: pressure forces and wake frequencies, J Wind Engineering and Industrial Aerodynamics, 1993, 49, pp 187–196.Google Scholar
19. Matsumoto, M. et al, Aerodynamic effects of the angle-of-attack on a rectangular prism, J Wind Engineering and Industrial Aerodynamics, 77 and 78, 1998, pp 531–542.Google Scholar
20. Laneville, A. and Lu, Z.Y. Mean flow patterns around two-dimensional rectangular cylinders and their Interpretation, J Wind Engineering and Industrial Aerodynamics, 1983, 14, pp 387–398.Google Scholar
21. Laneville, A., Gartshore, I.S. and Parkinson, G.V. An explanation of some effects of turbulence on bluff bodies’, 4th International Conference on Wind Effects on Buildings and Structures, London, UK, September 1975.Google Scholar
22. Robertson, J.M. ET AL, Wall pressures of separation-reattachment Flow on a square prism in uniform flow, J Industrial Aerodynamics, 2, 1977/78, pp 345–359.Google Scholar
23. Sant’Anna, F.A.D-M., Laneville, A., Trepanier, J.Y. and Lu, Z.Y. Detailed pressure field measurements for some 2-D rectangular cylinders, J Wind Engineering and Industrial Aerodynamics, 1988, 28, pp 241–250.Google Scholar
24. Mulhearn, P.J. Stagnation and reattachment lines on cylinder of square cross-section in smooth and turbulent flows, Nature Physical Science, 241, 26th February 1973, pp 165–167.Google Scholar
25. Leishman, J.G. Principles of Helicopter Aerodynamics, 2nd ed, Cambridge University Press, 2006.Google Scholar
26. Windsor, R.I. Wind tunnel tests of two models of rectangular containers, Wind Tunnel Report No 573. University of Maryland, Glenn L Martin Wind Tunnel, College Park, Maryland, USA, January 1970.Google Scholar
27. Briczinski, S.J. and Karas, G.R. Criteria for externally suspended helicopter loads, USAAMRDL TR-71-61, November 1971.Google Scholar
28. Watkins, T.C., Sinacori, J.B. and Kesler, D.F. Stabilization of externally slung helicopter loads, USAAMRDL TR-74-42, August 1974.Google Scholar
29. Laub, G.H. and Kodani, H.M. Wind tunnel investigation of aerodynamic characteristics of scale models of three rectangular shaped cargo containers, NASA TM-X 62169, July 1972.Google Scholar
30. Cicolani, L.S., Da Silva, J.G.A., Duque, E.P.N. and Tischler, M.B. Unsteady aerodynamic model of a cargo container for slung-load simulation, Aeronaut J, July 2004, 108, (1085).Google Scholar
31. Rosen, A., Cecuttam, S. and Yaffe, R., Wind tunnel tests of cube and CONEX Models, Technion report TAE-844, November 1999.Google Scholar
32. Sheldon, D.F. and Pryor, J. Study in depth of a single point and two point lateral and tandem suspension of rectangular box loads, Technical Note AM/38, Royal Military College of Science, May 1973.Google Scholar
33. Sheldon, D.F. and Pryor, J. A study on the stability and aerodynamic characteristics of particular military loads underslung from a Helicopter, Technical Note AM/40, Royal Military College of Science, April 1973.Google Scholar
34. Sheldon, D.F. and Pryor, J. The aerodynamic characteristics of various rectangular box and closed cylinder loads, Technical Note AM/41, Royal Military College of Science, April 1973.Google Scholar
35. Greenwell, D.I. A review of unsteady aerodynamic modelling for flight dynamics of manoeuvrable aircraft, AIAA-04-5276, AIAA Atmospheric Flight Mechanics Conference, August 2004.Google Scholar