Study on Influencing Factors of Helicopter Brownout Evolution Based on CFD-DEM
Source abstract
Abstract
The gas-solid two-phase flow model is constructed based on the Euler-Lagrangian framework. The SST k−ω two-equation turbulence model and the soft ball model are coupled by computational fluid dynamics (CFD) and a discrete element model (DEM). Brownout is then simulated by the above method with sliding mesh. As the calculation examples show, the simulations and experiments of the Lynx rotor and the Caradonna–Tung rotor are compared. The coupling method is verified through calculation of the rotor lift coefficient, blade section pressure coefficient and tip vortex shedding position. The results show that when the helicopter is hovering at a height of 0.52R from the ground, it will cause brownout and the pilot’s vision will be obscured by sand. When the hovering height is 1R, the phenomenon of brownout is not serious. The movement speed of most sand dust is about 12 m/s, and the height of the sand dust from the ground will gradually increase over time. Large particles of sand are more difficult to be entrained into the air than the small particles, and the particles with a radius of 50 um are basically accumulated on the ground. Moreover, the slotted-Tip rotor has an effect on restraining brownout.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Particle Dynamics in Fluid Flows · Fluid Dynamics and Turbulent Flows · Computational Fluid Dynamics and Aerodynamics
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China
References (21)
Show source-provided references
1. Bagnold, R.A. (1941). The Physics of Blown Sand and Desert Dunes Methuen, Springer.
2. Wachspress, D.A., Whitehouse, G.R., Keller, J.D., Yu, K., Gilmore, P., Dorsett, M., and McClur, K. (2009, January 27–29). A high fidelity brownout model for real-time flight simulations and trainers. Proceedings of the American Helicopter Society 65th Annual Forum, Grapevine, TX, USA.
3. Proposed mechanism for sediment entrainment by turbulent flows10.1029/JZ072i024p06183 ↗
4. Leese, G.W. (1964). Helicopter Downwash Blast Effects Study, US Army Engineer Waterways Experiment Station.10.21236/AD0452177 ↗
5. Rodgers, S.J. (1968). Evaluation of the Dusty Cloud Generated by Helicopter Rotor Downwash, Msa Research Corp.
6. Leishman, J. (2009, January 27–29). Investigation of Sediment Entrainment in Brownout Using High-Speed Particle Image Velocimetry. Proceedings of the 65th Annual American Helicopter Society Forum, Grapevine, TX, USA.
7. Fluid Dynamics of Interacting Blade Tip Vortices with a Ground Plane10.4050/JAHS.55.022005 ↗
8. The flow around a model helicopter main rotor in ground effect10.1007/s00348-011-1212-1 ↗
9. The interdependence of straining and viscous diffusion effects on vorticity in rotor flow fields
10. Syal, M., Govindarajan, B., and Leishman, J.G. (2010, January 11–13). Mesoscale sediment tracking methodology to analyze brownout cloud developments. Proceedings of the American Helicopter Society, 66th Annual Forum, Phoenix, AZ, USA.
11. Milluzzo, J.I. (2012). Effects of Blade Tip Shape on Rotor In-Ground-Effect Aerodynamics, University of Maryland.
12. Polzin, J.W., Guntupalli, K., and Rajagopalan, R.G. (2011, January 27–30). Discrete Blade Model for Rotorcraft Brownout. Proceedings of the 29th AIAA Applied Aerodynamics Conference, Honolulu, HI, USA.10.2514/6.2011-3182 ↗
13. Hance, B.T. (2012). Effects of Body Shapes on Rotor In-Ground-Effect Aerodynamics, University of Maryland.
14. Whitehouse, G.R., Wachspress, D.A., Quackenbush, T.R., and Keller, J.D. (2009, January 27–29). Exploring Aerodynamic Methods for Mitigating Brownout. Proceedings of the American Helicopter Society 65th Annual Forum, Grapevine, TX, USA.
15. Whitehouse, G.R., and Wachspress D A and Quackenbush, T.R. (2010, January 5–7). Aerodynamic Design of Helicopter Rotors for Reduced Brownout. Proceedings of the International Powered Lift Conference, Philadelphia, PA, USA.
16. Fan, L.S., and Zhu, C. (1999). Principles of Gas-Solid Flows, Cambridge University Press.10.1017/CBO9780511530142 ↗
17. Tip Vortex Geometry of a Hovering Helicopter Rotor in Ground Effect10.4050/JAHS.38.34 ↗
18. Caradonna, F.X., and Tung, C. (1981, January 8–11). Experimental and analytical studies of a model helicopter rotor in hover. Proceedings of the European Rotorcraft and Powered Lift Aircraft Forum, Moffett Field, CA, USA.
19. Caradonna, F.X., Laub, G.H., and Tung, C. (1984). An Experimental Investigation of the Parallel Blade-Vortex Interaction, Ames Reasearch Center.
20. Ahmad, J.U., and Strawn, R.C. (1999, January 25–29). Hovering rotor and wake calculations with an overset-grid Navier-Stokes solver. Proceedings of the 55th AHS International Annual Forum, Montreal, QC, Canada.
21. Mechanisms of dust diffuse pollution under forced-exhaust ventilation in fully-mechanized excavation faces by CFD-DEM10.1016/j.powtec.2017.04.045 ↗