Mechanics of Sound Generation in Flows

The Symposium on "The Mechanics of Sound Generation in FLows" th st was held in Gottingen, Germany, 28 - 31 August 1979, at the joint initiative of the International Union of Theoretical and Applied Mechanics (IUTAM), the International Commission on Acoustics (ICA) and the American Institute of Aeronautics and Astronautics (AIAA). From the whole field of flow-acoustics the Symposium concen trated on prob lems of sound generation, while sound propagation and the creation of flows by sound were left in the ba- ground. 82 delegates from 12 countries attended the Symposium. 38 papers were given 5 of which were invited general lectures. Emphasis was placed on discussion, a plenary discussion closing the sym- sium. A s care had been taken to invite as many active workers in the field as possible with their most recent results the Symposium provided a momentary overview of the current state of the ra pidly developing field of flow-acoustics. Participants appreciated the meeting as a possibility to inform themselves, to discuss their own results and to obtain incentives for future efforts.

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The Symposium on "The Mechanics of Sound Generation in FLows" th st was held in Gottingen, Germany, 28 - 31 August 1979, at the joint initiative of the International Union of Theoretical and Applied Mechanics (IUTAM), the International Commission on Acoustics (ICA) and the American Institute of Aeronautics and Astronautics (AIAA). From the whole field of flow-acoustics the Symposium concen­ trated on prob lems of sound generation, while sound propagation and the creation of flows by sound were left in the ba- ground. 82 delegates from 12 countries attended the Symposium. 38 papers were given 5 of which were invited general lectures. Emphasis was placed on discussion, a plenary discussion closing the sym- sium. A s care had been taken to invite as many active workers in the field as possible with their most recent results the Symposium provided a momentary overview of the current state of the ra­ pidly developing field of flow-acoustics. Participants appreciated the meeting as a possibility to inform themselves, to discuss their own results and to obtain incentives for future efforts.

Contenu
Tuesday, 28th August.- General Lecture: Why do the acoustics and the dynamics of a hypothetical mean flow bear on the issue of sound generation by turbulence?.- Sound radiation from a simulated jet flow.- Low frequency sound radiation due to the interaction of unsteady flows with a jet pipe.- Sound sinks in flows, a real possibility?.- Radiation properties of a turbulent jet excited by a sinusoidal acoustic disturbance.- The effects of upstream tones on the large scale instability waves and noise of jets.- Shear layer instability noise produced by various jet nozzle configurations.- On the radiation of sound by the instability waves of a compressible axisymmetric jet.- Sound generation by flow-acoustic coupling.- Near-wake structure and unsteady pressures at trailing edges of airfoils.- Investigation of trailing-edge noise.- Wednesday, 29th August.- General Lecture: Modelling low Mach number noise.- A study of production and stimulated emission of sound by vortex flows.- Aerodynamic sound generation by unsteady subsonic flows around rigid bodies.- Acoustic radiation from bodies in unsteady flows.- Influence of closely located solid surfaces on the sound spectra radiated by gas j ets.- Sound generation by head-on collision of two vortex rings.- Thursday, 30th August.- General Lecture: How powerful are the experimental techniques of sound source location in aero-acoustics; what prospects are there for an improvement?.- An evaluation of the Lighthill analogy for jet mixing noise generation: using LV turbulence, source location and spectral noise data.- Theory of cross-spectral densities of jet noise.- Some analytical considerations in jet noise prediction.- Theoretical and experimental study of wavelike disturbances in round free jet with emphasis being placed on orderly structures.- On the role of vortex pairing in jet noise generation.- Triple correlation of the pressure in subsonic circular jets and nonlinear interaction of instability waves.- On the role of surface shear stress fluctuations in hydroacoustics.- Flow acoustic interaction near a plane heat conducting compliant boundary.- A ray-theory approach for high-frequency engine-intake noise20.- On the form of the wall-pressure spectrum in a turbulent boundary layer in relation to noise generation by boundary layer-surface interactions.- Play tornado-like vortices a role in the generation of flow noise?.- Discrete frequency sound generation by fluid flows.- Friday, 31st August.- General Lecture: What good does industry expect from basic research in acoustics?.- Experimental determination of noise source mechanisms in gas turbine combustors.- A new view of sound generation and propagation in flows.- Importance of jet temperature on the prediction of jet noise in flight.- Excess noise from supersonic underexpanded jets in flight.- Mach wave radiation of hot supersonic jets.- General Lecture: The aeroacoustics of advanced turbopropellers.- Noise generation by transonic open rotors.