LOGIN TO YOUR ACCOUNT

Username
Password
Remember Me
Or use your Academic/Social account:

CREATE AN ACCOUNT

Or use your Academic/Social account:

Congratulations!

You have just completed your registration at OpenAire.

Before you can login to the site, you will need to activate your account. An e-mail will be sent to you with the proper instructions.

Important!

Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version of the site upon release.

Thank you for your patience,
OpenAire Dev Team.

Close This Message

CREATE AN ACCOUNT

Name:
Username:
Password:
Verify Password:
E-mail:
Verify E-mail:
*All Fields Are Required.
Please Verify You Are Human:
fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Languages: English
Types: Other
Subjects: TL

Classified by OpenAIRE into

arxiv: Physics::Fluid Dynamics
Interactions between the blades and vortical structures within the wake of a helicopter rotor are a significant\ud source of impulsive loading and noise, particularly in descending flight. Advances in the prediction and\ud understanding of such blade vortex interactions have been aided in recent years by the extensive experimental\ud dataset made available through the HART test programme. Brown’s Vorticity Transport Model was used to\ud predict the rotor blade loading, the resultant wake system and the acoustic noise radiation for the HART II\ud rotor. The vorticity conserving properties of the Vorticity Transport Model allow the detailed wake features\ud that are associated with blade vortex interactions to be resolved. The experimental airload data, in particular\ud the higher harmonic loading associated with blade vortex interactions, is matched well by the computations.\ud The computed vorticity distribution in the wake also shows good correlation with the experimentally measured\ud vortex positions. Including a representation of the fuselage within the computation yields marked improvement\ud in the prediction of the vortex positions compared to similar calculations with an isolated rotor. An accoustic\ud analysis, based on a Ffowcs-Williams Hawkings approach, is able to predict accurately the locations of the\ud sound pressure maxima and the upstream attenuation of the sound radiated by the rotor. The principal\ud discrepancies in airload, vortex position and acoustic prediction are confined almost exclusively to the rear of\ud the advancing side of the rotor and, if errors in measuring the blade deflection can be discounted, may be due\ud to minor inaccuracies in modelling the roll-up of the wake.
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • 1. van der Wall, B., Junker, B., Burley, C., Brooks, T., Yu, Y., Tung, C., Raffel, M., Richard, H., Wagner, W., Mercker, E., Pengel, K., Holthusen, H., Beaumier, P., and Delrieux, Y., “The HART II test in the LLF of the DNW - a Major Step towards Rotor Wake Understanding,” Proceedings of the 28th European Rotorcraft Forum, Bristol, England, 2002.
    • 2. van der Wall, B., Burley, C., Yu, Y., Richard, H., Pengel, K., and Beaumier, P., “The HART II test - Measurement of helicopter rotor wakes,” Aerospace Science and Technology , Vol. 8, No. 4, 2004, pp. 273 - 284.
    • 10. Brown, R. and Line, A., “Efficient HighResolution Wake Modelling using the Vorticity Transport Model,” AIAA Journal , Vol. 43, No. 7, 2005.
    • 11. Brown, R., “Rotor Wake Modeling for Flight Dynamic Simulation of Helicopters,” AIAA Journal , Vol. 38, No. 1, 2000.
    • 12. Kube, R., Splettstoesser, W. R., Wagner, W., Seelhorst, U., Yu, Y. H., Tung, C., Beaumier, P., J. Prieur, G. Rahier, P. S., Boutier, A., Brooks, T. F., Burley, C. L., Boyd, D. D., Mercker, E., and Pengel, K., “HHC aeroacoustic rotor tests in the GermanDutch wind tunnel: Improving physical understanding and prediction codes,” Journal of Pressure Vessel Technology , Vol. 2, No. 3, 1998, pp. 177 - 190.
    • 13. Toro, E., “A Weighted Average Flux Method for Hyperbolic Conservation Laws,” Proceedings of the Royal Society of London, Series A: Mathematical and Physical Sciences, Vol. 423, 1989, pp. 401-418.
    • 14. Kenyon, A. and Brown, R., “Wake Dynamics and Rotor - Fuselage Aerodynamic Interactions,” Proceedings of the American Helicopter Society 63rd Annual Forum, Virginia Beach, USA, 2007.
    • 15. Schneider, O., “Analysis of SPR measurements from HART II,” Aerospace Science and Technology , Vol. 9, No. 5, 2005, pp. 409 - 420.
    • 16. Schneider, O., van der Wall, B. G., and Pengel, K., “HART II Blade Motion Measured by Stereo Pattern Recognition (SPR),” Proceedings of the American Helicopter Society 59th Annual Forum, Phoenix, Arizona, 2003.
    • 17. Pengel, K., Mueller, R. H. G., and van der Wall, B. G., “Stereo Pattern Recognition - the technique for reliable rotor blade deformation and twist measurement,” Proceedings of the American Helicopter Society International Meeting on Advanced Rotorcraft Technology and Life Saving Activities (Heli Japan), Tochigi, Utsunomiya, Japan, 2002.
    • 18. van der Wall, B., “Mode identification and data synthesis of HART II blade deflection data,” IB 111- 2007/28, ftp://, 2007.
    • 19. Dietz, M., Kramer, E., and Wagner, S., “Tip vortex conservation on a main rotor in slow descent flight using vortex-adapted Chimera grids,” Proceedings of the AIAA Applied Aerodynamics Conference, Vol. 3, 2006, pp. 1776 - 1795.
    • 20. Lim, J. and van der Wall, B., “Investigation of the effect of a multiple trailer wake model for descending flights,” Proceedings of the American Helicopter Society 61st Annual Forum, 2005, pp. 1063 - 1081.
    • 21. Sim, B. and Lim, J., “Blade-vortex Interaction (BVI) noise and airload prediction using loose aerodynamic/structural coupling,” Proceedings of the American Helicopter Society 62nd Annual Forum, Phoenix, Arizona, USA, 2006.
    • 22. Farassat, F. and Succi, G. P., “A review of propeller discrete frequency noise prediction technology with emphasis on two current methods for time domain calculations,” Journal of Sound and Vibration, Vol. 71, No. 3, 1980, pp. 399-419. Elastic lag motion (Yel) coefficients (mm, R in metres)
  • No related research data.
  • Discovered through pilot similarity algorithms. Send us your feedback.

Share - Bookmark

Download from

Cite this article