Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-28T22:45:17.820Z Has data issue: false hasContentIssue false
  • English
  • Français

The Ffowcs Williams–Hawkings equation for hydroacoustic analysis of rotating blades. Part 1. The rotpole

Published online by Cambridge University Press:  23 May 2016

Sandro Ianniello
Sandro Ianniello*
Affiliation:
CNR–INSEAN, Marine Technology Research Institute, 00128 Rome, Italy
*
†Email address for correspondence: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

This paper deals with the use of the Ffowcs Williams–Hawkings equation for hydroacoustic analysis of rotating blades, and the deep difference between the acoustic fields generated by aeronautical and marine devices in air and underwater. This dissimilarity does not depend on either the different fluid or the (although existing) geometric and structural difference of the blade: it is an intrinsic feature of the generating noise mechanisms related to rotating sources and is essentially due to the remarkable diversity of the rotational speed. It will be shown how the usual assumption of believing the flow nonlinear sources to be negligible for blades rotating at low subsonic speed (coming from decades of research strictly limited to aeroacoustics) is totally wrong when applied to hydroacoustics. Such a goal is achieved through a practical approach, by analysing the general behaviour of the surface integral kernels of the solution for a rotating point source (here named rotpole), and by showing its relationship with a general multibladed device. This analysis suggests that the underwater noise prediction from a marine propeller is an inherently nonlinear problem and, contrary to analogous aeronautical configurations, it always requires an accurate estimation of the nonlinear flow sources just by virtue of the very low rotational speed.

JFM classification

Acoustics: Acoustics Acoustics: Aeroacoustics Acoustics: Hydrodynamic noise
Type
Papers
Information
Journal of Fluid Mechanics , Volume 797 , 25 June 2016 , pp. 345 - 388
Check for updates
Copyright
© 2016 Cambridge University Press 

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

Bagheri, M. R., Seif, M. S. & Mehdigholi, H. 2014 Numerical simulation of underwater propeller noise. J. Ocean Mech. Aerosp. Sci. Engng 4, 1–6.Google Scholar
Brentner, K. S. & Farassat, F. 1998 Analytical comparison of the acoustic analogy and Kirchhoff formulation for moving surfaces. AIAA J. 36 (8), 1379–1386.Google Scholar
Farassat, F. 1974 The acoustic far-field of rigid bodies in arbitrary motion. J. Sound Vib. 32 (3), 387–405.Google Scholar
Farassat, F. 1981 Linear acoustic formulas for calculation of rotating blade noise. AIAA J. 19, 1122–1130.Google Scholar
Farassat, F., Pegg, R. J. & Hilton, D. A. 1975 Thickness noise of helicopter rotors at high tip speed. In 2nd AIAA Aeroacoustics Conference, Hampton, 75–423.Google Scholar
Felli, M., Camussi, R. & Di Felice, F. 2011 Mechanisms of evolution of the propeller wake in the transition and far fields. J. Fluid Mech. 682, 5–53.Google Scholar
Ffowcs Williams, J. E. & Hawkings, D. L. 1969 Sound generation by turbulence and surfaces in arbitrary motion. Phil. Trans. R. Soc. 264 (A1151), 321–542.Google Scholar
Di Francescantonio, P. 1997 A new boundary integral formulation for the prediction of sound radiation. J. Sound Vib. 202 (4), 491–509.Google Scholar
Ianniello, S. 2007 New perspectives in the use of the Ffowcs Williams–Hawkings equation for aeroacoustic analysis of rotating blades. J. Fluid Mech. 570, 79–127.Google Scholar
Ianniello, S. 2012 Ship underwater noise prediction through the acoustic analogy. In International Conference on Advances and Challenges in Marine Noise and Vibration, MARNAV 2012, UK, Glasgow, 5–7 September. BMT Group Ltd.Google Scholar
Ianniello, S. 2014 The underwater noise prediction from marine propellers: an essentially nonlinear problem. In International Congress on Sound and Vibration ICSV 2014, Beijing, China, 13–17 July.Google Scholar
Ianniello, S. 2015 Sheet cavitation noise prediction from a marine propeller. In International Congress on Sound and Vibration ICSV 2015, Florence, Italy, 12–16 July. International Institute of Acoustics & Vibration.Google Scholar
Ianniello, S. & De Bernardis, E. 2015 Farassat’s formulations in marine propeller hydroacoustics. Intl J. Aeroacoust. 14 (1–2), 87–103.Google Scholar
Ianniello, S., Muscari, R. & Di Mascio, A.2011 Hydroacoustic characterization of a marine propeller through the acoustic analogy. In Proceedings of the 14th Congress of the International Maritime Association of the Mediterranean (IMAM), Genoa, Italy, 13–16 September 2011, Sustainable Maritime Transportation and Exploitation of Sea Resources, vol. 2 (ed. E. Rizzuto & C. Guedes Soares), pp. 991–1000. CRC Press.Google Scholar
Ianniello, S., Muscari, R. & Di Mascio, A. 2013 Ship underwater noise assessment by the acoustic analogy. Part I: nonlinear analysis of a marine propeller in a uniform flow. J. Mar. Sci. Technol. 18 (4), 547–570.Google Scholar
Ianniello, S., Muscari, R. & Di Mascio, A. 2014a Ship underwater noise assessment by the acoustic analogy. Part II: hydroacoustic analysis of a ship scaled model. J. Mar. Sci. Technol. 19 (1), 52–74.Google Scholar
Ianniello, S., Muscari, R. & Di Mascio, A. 2014b Ship underwater noise assessment by the acoustic analogy. Part III: measurements versus numerical predictions on a full-scale ship. J. Mar. Sci. Technol. 19 (2), 125–142.Google Scholar
Morfey, C. L. & Tanna, H. K. 1971 Sound radiation from a point force in circular motion. J. Sound Vib. 15 (3), 325–351.Google Scholar
Muscari, R., Di Mascio, A. & Verzicco, R. 2013 Modeling of vortex dynamics in the wake of a marine propeller. Comput. Fluids 73, 65–79.Google Scholar
Pan, Y. & Zhang, H. 2013 Numerical prediction of marine propeller noise in non-uniform inflow. Chin. Ocean Engng 27 (1), 33–42.Google Scholar
Poletti, M. A. 2010 Series expansions of rotating two and three dimensional sound fields. J. Acoust. Soc. Am. 128 (6), 3363–3374.Google Scholar
Poletti, M. A. & Teal, P. D. 2011 Comparison of methods for calculating the sound field due to a rotating monopole. J. Acoust. Soc. Am. 129 (6), 3513–3520.Google Scholar
Salvatore, F. & Ianniello, S. 2003 Preliminary results on acoustic modeling of cavitating propellers. Comput. Mech. 32 (4/6), 291–300.Google Scholar
Seol, H., Jung, B., Suh, J. C. & Lee, S. 2002 Prediction on non-cavitating underwater propeller noise. J. Sound Vib. 257 (1), 131–156.Google Scholar
Seol, H., Suh, J. C. & Lee, S. 2005 Development of hybrid method for the prediction of underwater propeller noise. J. Sound Vib. 288 (1/2), 345–360.Google Scholar
Tang, H., Qi, D. & Mao, Y. 2013 Analysis on the frequency-domain numerical method to compute the noise radiated from rotating sources. J. Sound Vib. 332, 6093–6103.Google Scholar
Tanna, H. K. & Morfey, C. L. 1971 Sound radiation from point sources in circular motion. J. Sound Vib. 16 (3), 337–348.Google Scholar
Ye, J., Xiong, Y., Xiao, C. & Bi, Y. 2010 Prediction of non-cavitation propeller noise in time domain. Chin. Ocean Engng 25 (3), 531–538.Google Scholar