Hostname: page-component-848d4c4894-sjtt6 Total loading time: 0 Render date: 2024-07-02T23:51:10.707Z Has data issue: false hasContentIssue false
  • English
  • Français

Rotor wake interactions with an obstacle on the ground

Published online by Cambridge University Press:  06 March 2018

D.J. Pickles ,
R.B Green  and
M. Giuni
D.J. Pickles*
Affiliation:
Aerospace Science Division, School of Engineering, University Of Glasgow, Glasgow, United Kingdom
R.B Green
Affiliation:
Aerospace Science Division, School of Engineering, University Of Glasgow, Glasgow, United Kingdom
M. Giuni
Affiliation:
Aerospace Science Division, School of Engineering, University Of Glasgow, Glasgow, United Kingdom
*
[email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

An investigation of the flow around an obstacle positioned within the wake of a rotor is described. A flow visualisation survey was performed using a smoke wand and particle image velocimetry, and surface pressure measurements on the obstacle were taken. The flow patterns were strongly dependent upon the rotor height above the ground and obstacle, and the relative position of the obstacle and rotor axis. High positive and suction pressures were measured on the obstacle surfaces, and these were unsteady in response to the passage of the vortex driven rotor wake over the surfaces. Integrated surface forces are of the order of the rotor thrust, and unsteady pressure information shows local unsteady loading of the same order as the mean loading. Rotor blade-tip vortex trajectories are responsible for the generation of these forces.

Keywords

Helicopterground effectrotor wakevortex interaction
Type
Research Article
Information
The Aeronautical Journal , Volume 122 , Issue 1251 , May 2018 , pp. 798 - 820
Copyright
Copyright © Royal Aeronautical Society 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Fradenburgh, E.A. The helicopter and the ground effect machine, J American Helicopter Soc, October 1960, 5, (4), pp 24–33.CrossRefGoogle Scholar
2.Lee, T.E., Leishman, J.G. and Ramasamy, M. Fluid dynamics of interacting blade tip vortices with a ground plane, J American Helicopter Soc, April 2010, 55, (2), pp 22005.Google Scholar
3.Knight, M. and Hefner, R.A. Static thrust analysis of the lifting airscrew, NACA-TN-626, Washington, DC, US, December 1937.Google Scholar
4.Hayden, J.S. The effect of the ground on helicopter hovering power required, 32nd Annual Forum of the American Helicopter Society, 1976, Washington, D.C., US, 55, (2), pp 10–12.Google Scholar
5.Betz, A. The ground effect on lifting propellers. NACA Technical Memorandums no.836, Washington, D.C., USA, 1937.Google Scholar
6.Nathan, N. and Green, R. Measurements of a rotor flow in ground effect and visualization of the brown-out phenomenon, 64th American Helicopter Society Annual Forum, 2007, Montreal, Canada.Google Scholar
7.Quinliven, T.A. and Long, K.R. Rotor performance in the wake of a large structure, 65th American Helicopter Society Annual Forum, 27-29 May 2009, Grapevine, TX, US.Google Scholar
8.Johnson, B., Leishman, J.G. and Sydney, A. Investigation of sediment entrainment using Dual-Phase, High-Speed particle image velocimetry, J American Helicopter Soc, 2010, 55, (4), pp 42003.Google Scholar
9.Phillips, C. and Brown, R.E. Eulerian simulation of the fluid dynamics of helicopter brownout, J Aircr, 2009, 46, (4), pp 1416–1429.Google Scholar
10.Wadcock, A.J., Ewing, L.A., Solis, E., Potsdam, M. and Rajagopalan, G. Rotorcraft downwash flow field study to understand the aerodynamics of helicopter brownout, National Aeronautics and Space Administration, Moffett Field, CA, USA, Ames Research Center, 2008.Google Scholar
11.Timm, G.K. Obstacle-induced flow recirculation, J American Helicopter Soc, 1965, 10, (4), pp 5–24.Google Scholar
12.Crozon, C., Steijl, R. and Barakos, G.N. Numerical study of helicopter rotors in a ship airwake, J Aircr, 2014, 51, (6), pp 1813–1832.Google Scholar
13.Nacakli, Y. and Landman, D. Helicopter downwash/frigate airwake interaction flowfield PIV surveys in a low speed wind tunnel, Annual Forum Proceeding - AHS Int, 2011, 4, pp 2988–2998.Google Scholar
14.Gibertini, G., Grassi, D., Parolini, C., Zagaglia, D. and Zanotti, A. Experimental investigation on the aerodynamic interaction between a helicopter and ground obstacles, Proceedings of the Institution of Mech Engineers, Part G: J Aerospace Engineering, 2015, 229, (8), pp 1395–1406.Google Scholar
15.Visingardi, A., De Gregorio, F., Schwarz, T., Schmid, M., Bakker, R., Voutsinas, S., Gallas, Q., Boisard, R., Gibertini, G., Zagaglia, D., Barakos, G., Green, R., Chirico, G. and Giuni, M. Forces on obstacles in rotor wake – a GARTEUR action group, 43rd European Rotorcraft Forum, Milano, Italy, 12-15 September, 2017Google Scholar
16.Thielcke, W. and Stamhuis, E.J. Towards user-friendly, affordable and accurate digital particle image velocimetry in MATLAB, J Open Research Software, 2014, 2, (1).Google Scholar
17.Doligalski, T.L., Smith, C.R. and Walker, J.D.A. Vortex interactions with walls, Annual Review of Fluid Mech, 1994, 26, pp 573–616.Google Scholar
18.Milluzzo, J.J. and Leishman, J.G. Vortical sheet behavior in the wake of a rotor in ground effect, AIAA J, 2017, 55, (1), pp 24–35.Google Scholar
19.Ramasamy, M., Johnson, B. and Leishman, J.G. Turbulent tip vortex measurements using dual-plane stereoscopic particle image velocimetry, AIAA J, 2009, 47, (8), pp 1826–1840.Google Scholar