On the sound field of a rotating propeller

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August undefined, 2024

WebDOI: 10.1016/j.oceaneng.2024.114283 Corpus ID: 257994679; Numerical study on unsteady propeller exciting characteristics considering shafting whirling vibration effect @article{Meng2024NumericalSO, title={Numerical study on unsteady propeller exciting characteristics considering shafting whirling vibration effect}, author={Chang-Lin Meng … Web9 de jan. de 2024 · "The sound field of a rotating propeller is treated theoretically on the basis of aerodynamic principles. For the lower harmonics, the directional …

Radiation Modes of Propeller Tonal Noise Journal of Vibration …

Web19 de mai. de 2015 · 13. The main advantage of contra-rotating props is the increased efficiency (6 to 16% according to Wikipedia). Another advantage is that the torque is pretty much cancelled out by the contra … Web31 de ago. de 2024 · The sound field properties of non-cavitating marine propellers are investigated using a hybrid method, in which the FWH (Ffowcs William-Hawkings) analogy is coupled with the BEM (Boundary Element Method) approach. The investigations include both the uniform and non-uniform inflow conditions. For both conditions, the dominant … raymond pitcairn children

The asymptotic theory of rapidly rotating sound fields

WebTime-domain analysis of contra-rotating propeller noise: wake interaction with a downstream propeller blade ... C. J. 1988 b Shocks and singularities in the pressure field of a supersonically rotating propeller. J. ... Predicting the aerodynamic noise of counter-rotating coaxial rotors. Journal of Sound and Vibration, Vol. 547, Issue. , p. 117487. WebAlso, it could reduce the far-field URN by over 3dB overall sound pressure level (OASPL) through disruption of the coherent wake structure in the propeller slipstream. It was found that LE tubercle modified ducted propeller blades could improve propulsive efficiency by up to 6.5% when comparing at the same thrust loading condition. Web1 de jun. de 2000 · The employed method captures the complexity of the acoustic field generated by the interactions of the propeller sound fields among each other and ... raymond piper artist

Shocks and singularities in the pressure field of a supersonically ...

Computational fluid dynamics and hydroacoustics analyses of …

WebThe sound field of a rotating propeller is teated theoretically on the basis of aerodynamic principles. For the lower harmonics, the directional characteristics and the radiated sound energy are determined and are in conformity with existing experimental results. Author(s): L. Gutin Indexed under: None; WebRotating sound fields 259 is related to previous work. The results suggest a number of further investigations, indicated briefly in §5. 2. Rayleigh’s integral (a) Thickness noise A … raymond pitetWebHá 6 horas · Irrigation canals in the U.S. are made of concrete or stone and transport water from main sources to fields. Emrgy units look something like a propeller with blades rotating parallel to the ground. raymond pippins little rock

"Web1 de jan. de 2024 · Abstract. This chapter introduces the widely applied frequency domain and time-domain methods of propeller noise and discusses in detail how to realize a numerical solution for the time-domain ... " - On the sound field of a rotating propeller

On the sound field of a rotating propeller

Investigation_on_the_dynamic_properties_of_propell

WebEng. 469 012099 [19] Qu Y, Su J, Hua H and Meng G 2024 Structural vibration and acoustic radiation of coupled propeller-shafting and submarine hull system due to propeller forces J. Sound Vib. [20] Zhang C and Huang Q 2024 Experimental research on the characteristics of ship propulsion system under dynamic excitations 2024 4th International Conference … Web11 de abr. de 2024 · Assuming that the number of blades on both propellers is large, we evaluate the integral asymptotically in terms of its leading-order contributions from …

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Webpropeller blades which will cause additional noise at the BPF. When this new sound field is added to that due to the steady loading with proper consideration being given to the phasing between the two sources, a resultant non-axisymmetric sound field is obtained. As will be shown in the next section, for lightly loaded propellers, especially with WebGutin, L.: 1936 On the sound field of a rotating airscrew. NACA TM 1195.Google Scholar. Hanson, D. B.: 1980 Helicoidal surface theory for harmonic noise of propellers in the far …

WebBoth the near and far acoustic fields of propellers are of interest, with the near field influencing unsteady airframe loading and passenger comfort, and the far field determining the noise level near airports. The propeller is also a major source of noise for underwater vehicles. Keywords. Frequency Ratio; Acoustic Field; Sound Field; Retarded ... Web24 de mai. de 2024 · Overall sound pressure levels, far-field spectra, and directivities (overall SPL, tones, and broadband) are assessed to determine trade-offs and optimal choices in designing a contra-rotating ...

WebAbstract: The sound field of a rotating propeller is teated theoretically on the basis of aerodynamic principles. For the lower harmonics, the directional characteristics and the … Web1 de abr. de 2024 · The solution obtained may be of particular interest for propeller and rotor noise measurements in open ... Numerical simulations of rotating sound fields are presented to verify the theory. (c ...

WebHá 2 dias · where the subscripts “m” and “s” denote the master and slave, respectively. 2.1.1 The Guyan Reduction. In the 1960s, Guyan [], as a pioneer in the field of reduction technology, proposed the well-known Guyan reduction method.Almost at the same time, similar methods were introduced by Irons [20, 21] and is generally referred to as static …

Webposition rs. These waves form a rotating sound field: for example a harmonic component of the thickness noise of a rotating propeller with no forward motion (Chapman 1992, … raymond pitcairnWeb12 de abr. de 2024 · A first principles understanding of the sound field produced by multirotor drones in hover is presented. Propeller diameters ranging from 8 to 12 in. are examined and with configurations comprising an isolated rotor, quadcopter, and hexacopter configuration. The drone pitch, defined as the ratio of drone diameter to rotor diameter, is … raymond pirtle nashville tnWeb22 de jun. de 1988 · The noise fields from the rotors of counter-rotating propellers having the same number of blades and angular frequency tend to cancel or reinforce … raymond pizzoferrato obituary new britain ctWeb5 de mai. de 2024 · The acoustic field is considered as a superposition of fields formed by the radiations ... On the acoustic field of a rotating propeller, Zh. Tekh. Fiz., 6, No. 5 ... E. Ya. Nepomnyashchii, Study and calculation of the sound of a propeller, Tr. TsIAM, Issue 39, 71−78 (1941). A. G. Munin and V. E. Kvitka (Eds.), Aviation ... simplify 12 over 10Web513 magnitude of the sonic radius c/Q, and 0 < 1; by definition, g{r,6) = 0 off the blades. Dimensionless lengths r = Qr/c, etc., based on the sonic radius, will be used henceforth, so that the dimensionless radius a of the propeller is just the tip Mach number, and the chord section is 2 = +eg(r,d). The function g, being periodic in 6, may be decomposed into … simplify 12 over 108Web1 de nov. de 2012 · M. V. Lowson, The sound field for singularities in motion, Proc. Royal Soc. (London), Ser. A, 286, 1407 (1965). MathSciNet Google Scholar V. F. Samokhin, … raymond pitt doddingtonWebPassionate about fluid dynamics and applied mathematics, I investigate aerodynamic noise generation in order to reduce the environmental impact of aero engines and ventilation systems. Through this research activity, I developed skills in mathematical modelling of physical systems, machine learning, statistics, optimisation and computational simulation … raymond pittman obituary