Last edited by Yozshulkis

Friday, July 24, 2020 | History

3 edition of **Sound radiation from a lifting rotor generated by asymmetric disc loading** found in the catalog.

Sound radiation from a lifting rotor generated by asymmetric disc loading

S. E. Wright

- 248 Want to read
- 21 Currently reading

Published
**1968**
by University of Southampton, Institute of Sound and Vibration Research] in [Southampton, Eng
.

Written in English

- Rotors (Helicopters),
- Airplanes -- Noise.

**Edition Notes**

Statement | by S. E. Wright. |

Series | I.S.V.R. technical report no. 5 |

Classifications | |
---|---|

LC Classifications | TA355 .S585 no. 5 |

The Physical Object | |

Pagination | 21, [17] l. |

Number of Pages | 21 |

ID Numbers | |

Open Library | OL4370223M |

LC Control Number | 78541021 |

Thrust loading is in the units of pound per horsepower and is a function of power and rotor disk area. Thrust loading (TL) is calculated: TL [lb/hp]= * PL^() Now that thrust loading is calculated, we can find the total thrust of the propeller (or lift of the rotor). Lift . Radiation from a Circular Baffled Piston That is, the sound energy produced by the speaker becomes channeled into a preferred direction and very little energy is radiated at other directions. In the animation below the radiated sound is pretty much contained within a cone of 55 o from the center axis. Also, from the darkness of the contour.

Vibration and sound radiation analysis of the final drive assembly considering the gear-shaft coupling dynamics Yawen Wang, Junyi Yang, Dong Guo, and Teik C Lim Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science , Rotors (and wings) generate lift by accelerating air downwards. The lift is proportional to the rate of change of inertia of the air. The amount of air affected is proportional to the area of the rotor disk (the whole area in which the blades move) and that is simply ($\pi\times$) square of blade length. So in a sense the answer is easy.

Sound Radiation from a Disk Brake Rotor Using a Semi-Analytical Method Modal sound radiation of a brake rotor is expressed in terms of analytical solutions of a generic thick annular disk having similar geometric dimensions. Finite element method is used to determine structural modes and response. Vibro-acoustic responses such as. Based on more than 30 years of research and practical experience, Sound and Vibrations of Positive Displacement Compressors is the first book to combine theory and design guidelines dedicated solely to .

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Sound Vib. () 9 (2), SOUND RADIATION FROM A LIFTING ROTOR GENERATED BY ASYMMETRIC DISK LOADING S. WRIGHT Institute of Sound and Vibration Research, University of Southampton, Southampton, S09 5NH, England (Received 7 August ) The state of the art is such that all free-field rotors, including helicopters, propellers and fans, produce acoustic spectra which fall Cited by: The state of the art is such that all free-field rotors, including helicopters, propellers and fans, produce acoustic spectra which fall short of matching existing theories; in particular, discrete radiation cannot be predicted accurately.

The theory described here proposes that rotational noise is the dominant rotor noise mechanism and neglects vortex noise as being an appreciable noise. M.J. LIGHTHILLOn sound generated aerodynamically: I. General theory. CARLEY,Journal of Sound and Vibration,Sound radiation from propellers in forward flight.

S.E. WRIGHTSound radiation from a lifting rotor generated by asymmetric disk loading. Journal of Sound and Vibration, 9 (), pp. Google Cited by: 5. An exact series expansion for the field radiated by a monopole ring source with angular variation in source strength is derived from a previously developed expression for the field from a finite disk.

The derived series can be used throughout the field, via the use of a reciprocity relation, and can be readily integrated to find the field radiated by arbitrary circular sources of finite extent Cited by: 8.

REFERENCES 1. WRIGHT Journal of Sound and Vibrat The acoustic spectrum of axial flow machines. WRIoHT Journal of Sound and Vibration 9, Sound radiation from a lifting rotor generated by asymmetric disk loading. : V.J. Virchis, S.E.

Wright. Read the latest articles of Journal of Sound and Vibration atElsevier’s leading platform of peer-reviewed scholarly literature.

Wright, S.E.: Sound radiation from a lifting rotor generated by asymmetric disc loading. Sound and Vibr. 9 () – Broadband and discrete frequency radiation from subsonic rotors. Sound and Vibr. 36 () – ADS CrossRef Google Scholar.

Amiet, R.K.: Noise produced by turbulent flow into a propeller or helicopter. A spherical harmonic expansion for the sound field due to a rotating oscillating point source has recently been derived. This paper provides further confirmation of the expansion results by comparing it with two known numerical approaches to determining the sound field.

In the advanced time approach—applicable for Mach numbers below 1—the sound at transmission time determines the field at. The effect of turbulent loading on the noise radiated by an advanced aircraft propeller is assessed using a spectral conditioning technique which allows the inclusion of the non-linear effects associated with source rotation.

S.E. WRIGHTSound radiation from a lifting rotor generated by asymmetric disk loading. Journal of Sound and Vibration. Book Search tips Selecting this option will search all publications across the Scitation platform Selecting this option will search all publications for “ The radiation of sound from a propeller at angle of attack,” Proc.

R “ Sound radiation from a lifting rotor generated by asymmetric disk loading,” J. Sound. An analysis is developed linking the form of the sound field from a circular source to the radial structure of the source, without recourse to far-field or other approximations.

It is found that the information radiated into the field is limited, with the limit fixed by the wavenumber of the source multiplied by the source radius (Helmholtz number). Sound radiation from a lifting rotor Wright, Selwyn Edgar () Sound radiation from a lifting rotor.

University of Southampton, Institute of Sound and Vibration Research, Doctoral Thesis, pp. Record type: Thesis (Doctoral) Other. PDF - Other. Sound radiation from a lifting rotor generated by asymmetric disk loading,” (). Stereo Pattern Recognition – the technique for reliable rotor blade deformation and twist measurement,”.

this void, we investigate sound radiation from a simplified brake rotor in this article. A semi-analytical procedure is proposed that is based on structural eigen-solutions from finite element analysis and analytical modal sound radiation solutions developed for a thick annular disk.

b z h a r H disk hat t Figure 1. A thick annular disk with a. radiation generated at a point, while real sound is always generated over some area and can be described only by a continuous distribution of point singularities.

Physical models, taken from Ref. 2, are shown in Fig. The simplest of these is the pulsating sphere, which is used to represent the simple point source where the sound.

An analytical solution for the sound radiation from the rotating sound source, which considers motion compensation and a uniform subsonic axial flow, is deduced. Simulations on a rotating point.

1 Notation 2 wave operator, 2= 1 c2 @2 @t2 ¡r c sound speed in quiescent medium f = 0 function that describes the source surface, e.g., a rotor blade g = ¿ ¡t+r=c H(f) Heaviside function, H(f) = 0 for f 0 ‘i components of local force intensity that acts on the ﬂuid, ‘i = Pijnj ‘r ‘iˆri r ‘˙ iˆri M local Mach number vector of source with respect to a.

A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) and a control system that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight.

Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter tail rotor, which. Disc Loading and Hover Efficiency. Disc loading relates the weight of an aerial vehicle (e.g. a helicopter or multicopter) with the area, called rotor disc area, that the rotor(s) sweep(s).

Often it is then standardized into kg/sqm or lb/sqf. Hover efficiency relates the weight of an aerial vehicle with the power required to keep it aloft in hover.

Stewart Glegg's research works with 1, citations and 3, reads, including: The effect of shear sheltering on trailing edge noise. The computer code implements a vortex method from finite span wing theory and determines the induced velocity at the rotor disk by integrating the Biot-Savart law. an Asymmetric High-Lift.The analysis is based on Lighthill's aerodynamic sound equation, modified to allow for a uniform mean flow, and is restricted to low‐solidity rotors (lifting line approximation).The sound pressure at P caused by N monopoles can be given as ~p(;r) ˇ i!ˆq0 4ˇr e ikr " sin Nˇd cos sin ˇd cos # (R&F:()) which consists of sound pressure of a monopole directivity function (note that book version of R&F uses a number of 2N monopoles) Sound Radiation from Vibrating Objects18/20 Jyri Pakarinen/Archontis Politis