Published 6 issues per year
ISSN Print: 1948-2590
ISSN Online: 1948-2604
COMPUTATION OF MAIN ROTOR NOISE DUE TO BLADE THICKNESS
ABSTRACT
The problem of noise generated by a main rotor due to a thickness of its blades, that is, of a displacement noise or volume noise, is considered. This is one of the components of impulse noise, which is connected to the phenomena taking place at a sharp displacement of air by rotating blades at the expense of their 3D thickness. A technique of a displacement noise calculation based on the linear acoustic theory with an assumption of a blade thickness to be constant over time is described. A function of the influence of each volume element has a simple and quite universal form, and enables us to easily analyze the dependence of the noise on the blade construction parameters, particularly on the shape of the blade tip. The calculation results are presented. The results of the maximum sound pressure, obtained using the proposed technique, are compared with data of flight tests. A satisfactory agreement of calculation and test data is shown.
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Baskin, V. E., Acoustical Pressure Caused by the Helicopter Propeller at a Horizontal Flight.
-
Baskin, V. E., To the Linear Theory of Nonstationary Motion of Gas under the Influence of Nonpotential External Forces.
-
Gutin, L. Ya., On a "Rotation Sound" of Air Propeller.
-
Hubbard, H. and Regier, A., Free-Space Oscillating Pressures near the Tips of Rotating Propellers.
-
Johnson, W., Helicopter Theory.
-
Lowson, M. V. and Ollerhead, J. B., A Theoretical Study of Helicopter Rotor Noise.
-
Mauffrey, Y., Rahier, G., and Prieur, J., Numerical Investigation on Blade-Wake Interaction Noise: Toward a Better Understanding of BWI Mechanisms.
-
Munin, A. G., Aviation Acoustics.
-
Richardson, I. D., Several Questions of Applied Acoustics.
-
Rosen, G. and Rohrbach, C., The Quiet Propeller - A New Potential.
-
Samokhin, V. F. and Rozhdestvensky, M. G., External Noise of Single Rotor Helicopters.
-
Schmitz, F. H. and Boxwell, D. A., In-Flight Far-Field Measurement of Helicopter Impulsive Noise.
-
Sim, B.W.-C. and Lim, J.W., Blade-Vortex Interaction (BVI) Noise and Airload Prediction Using Loose Aerodynamic Structural Coupling.
-
Vause, C. R., Schmitz, F. H., and Boxwell, D. A., High-Speed Helicopter Impulsive Noise.