Validation of a Time Domain Formulation for Propeller Noise Prediction

Abstract

The present paper is oriented at the definition of a series of validation test cases for the far-field subsonic formulation of Farassat in the time domain, solving the Lighthill analogy for aeroacoustics in the Ffowcs William-Hawkings formulation for far-field noise predictions. The focus will be on the definition, validation and verification of four test cases for far-field acoustic propagation. The test cases are: (i) a rotating rotor with a pre-defined body force, (ii) a translating and rotating small disk case with a moving observer, (iii) a conventional helicopter rotor case, (iv) and the consistency test known as the Isom thickness noise. The acoustic pressure signature, sound pressure level and directivity have been calculated for each test case. Graphical outputs and comparisons of results with those of analytical solutions are presented.

Get full access to this article

View all access options for this article.

References

Lighthill

M.J.

, (1952). “On sound generated aerodynamically. Part 1. General theory”, proceeding of the Royal Society (a) 211, pp. 564–587.

Williams

Ffowcs J. E.

and Hawkings

D. L.

, (1969). “Sound generation by turbulence and surfaces in arbitrary motion”, Philosophical transactions of Royal Society, London, (A), pp. 264, 321–342.

Blake

W.K.

, “Mechanics of Flow Induced Sound and Vibration”, Academic Press, 1996.

Brentner

K. S.

Farassat

(2003). “Modeling aerodynamically generated sound of helicopter rotors”, Progress in Aerospace Sciences, 39, pp. 83–120.

Farassat

and Succi

G.P.

(1983). “The prediction of helicopter rotor discrete frequency noise”, Vertica, Vol. 7, No. 4, pp. 309–320.

Farassat

(1981). “Linear acoustic formulas for calculation of rotating blade noise”, AIAA Journal, Vol. 9, pp. 1122–1130.

Hirsch

Ch.

Ghorbaniasl

Gh.

Ramboer

, (2003). “Fan noise simulation in the time domain: Validation test cases”, the second international symposium on Fan Noise, Senlis (France)

Tam

(2000). “Rotor noise: Category 2, Analytical solution”, Third Computational Aeroacoustics (CAA) Workshop on Benchmark Problems, NASA/CP-2000-209790.

Isom

M. P.

, (1975). “The theory of sound radiated by a hovering transonic helicopter blade”, Poly-AE/AM, No. 75–4, Polytechnic Institute of New York.

10.

Hanson

D. B.

and Frink

M. R.

(1979). “The importance of quadrupole sources in prediction of transonic tip speed propeller noise”, Journal of Sound and Vibration, Vol. 62, No.1, pp. 19–38.

11.

Rienstra

S.W.

and Hirschberg

(2002). “An introduction to acoustics”, (http://www.win.tue.nl/∼sjoerdr/papers/boek.pdf).

12.

Johnson

Wayne

, (1980). “Helicopter theory”, Princeton University Press, pp 7.

13.

Brentner

K. S.

(1986). “Prediction of Helicopter Rotor Noise. A Computer Program Incorporating Realistic Blade Motions and Advanced Formulation”, NASA Report TM-87721.

14.

Farassat

(1979). “The derivation of a thickness noise formula for the far-field by Isom”, Journal of sound and vibrations, 64(1) 159–160.

15.

Farassat

(1979). “Extension of Isom's thickness noise formula for the near field”, Journal of sound and vibrations, 67(2) 280–281.

16.

Farassat

(1980). “Isom thickness noise formula for rotating blades with finite thickness at the tip”. Journal of Sound and Vibration, Vol. 72(4), pp. 550–553.

17.

Farassat

, (1977). “Discontinuities in aerodynamics and aero-acoustics: The concept and application of generalized derivatives”, Journal of sound and vibrations, Vol. 55, pp. 165–193.

18.

Farassat

(1983). “A note on the tip noise of rotating blades”. Journal of Sound and Vibration, Vol. 86(3), pp. 449–453.