Aero- And Hydro-Acoustics: Iutam Symposium, Ecole Centrale de Lyon, 3-6 July, 1985

ISBN-13: 9783642827600 / Angielski / Miękka / 2012 / 550 str.

Genevieve Comte-Bellot; John E. Fowcs-Williams

Opis

The Symposium "Aero-and Hydroacoustics" was held at the Ecole Centrale de Lyon, France, on 3rd - 6 July 1985, at the initiative of the International Union of Theoretical and Applied Mechanics (IUTAM) . The research topics discussed concerned the acoustics of unstable and turbulent flows and the noise generated by movable surfaces. Other subjects of interest were thermoacoustics, diffraction, and acoustic propagation through turbulence. Applications of numerical and experimental techniques to source diagnostics were discussed, as was active noise control. In Hydroacoustics the emphasis was on noise due to flow induced vibrations. There were 8 general invited lecturers and 43 other contributors, with 150 participants form 14 countries. Sufficient time was provided for discussions and social gatherings. For example, there was the opening of the high speed anechoic wind tunnel of the Centre Acoustique, and a welcome address given by the Mayor of Lyon in his historic City Hall. The organizing Committee of the Symposium wish to express their thanks to la Direction des Recherches Etudes et Techniques du Ministere des Armees (DRET), Ie Centre National de la Recherche Scientifique (CNRS), Ie Conseil General du Rhone, l'Association Universitaire de Mecanique (AUM), Ie Ministere de l'Environnement, for financial support. Le Groupement des Acousticiens de langue frangaise (GALF) helped advertise the meeting. The organizers are also indebted to the International Union of Theoretical and Applied Mechanics for providing travel subsidies to young scientists.

Spis treści

Session I — “Diffraction.- Diffraction and radiation.- Influence of airfoil mean loading on convected gust interaction noise.- Acoustic waves emitted by vortex-body interaction.- Non-steady flow over a trailing edge — An experimental study.- An experimental study of the influence of mean flow on acoustic dissipation by vorticity production at edges.- Session II — “Active Control”.- Active noise control.- The constraint of causality on an active control system.- Acoustic pressure and intensity distributions in finite length active noise control systems.- The active minimisation of harmonic enclosed sound fields.- Session III — “Source Mechanisms”.- Source identification techniques — A critical evaluation.- Sound generation in the ocean under a turbulent airflow.- Acoustic radiation fron vortex solitons.- Session IV — “Rotor Noise”.- Noise of high speed surfaces.- Comparison of two propeller source models for aircraft interior noise studies.- Modelling of trailing edge flow tones in elastic structures.- The Ffowcs Williams-Hawkings equation-fifteen years of research.- Session V — “Thermo Acoustics”.- Thermoacoustic sources.- Active control of the noise from a Rijke tube.- Coherence aspects of acoustic wave transmission through a medium with temperature fluctuations.- Session VI — “Computational Acoustics”.- Numerical methods in acoustics.- Computational aeroacoustics — Present status and future promise.- The wavenumber-frequency spectrum of the wall pressure field computed from a numerical solution of the Navier Stockes equation.- A mixed functional for the numerical resolution of fluid-structure interaction problems.- Rayonnement d’une plaque mince, homogène ou raidie, encastrée dans un plan parfaitement rigide.- Session VII — “Hydroacoustics”.- Topics in hydroacoustics.- Interaction hydroélastique entre une plaque et un écoulement.- The acoustics of disturbed steady motions.- Temporal variability in shallow water acoustic transmission and its correlation with the environment.- Underwater sound generation by waterhammer.- Session VIII — “Hydroacoustics (C’ nd)”:.- Finite amplitude sound beams resulting from nonlinear vibration of a circular membrane undergoing axisymmetric resonant excitation.- Theoretical prediction for the reduction of flow-induced noise on a plane surface.- The vibration of a periodically ring-stiffened, fluid-loaded cylinder.- Surface inpedance loading of panels.- Session IX — “Flow Noise”.- Excitation of instability waves.- On noise generated by turbulence in a pipe downstream of a discontinuous area enlargement.- Acoustoelasticity of a panel backed by a rectangular cavity.- Near field pressure fluctuations of a circular jet.- Experimental investigation of near and far acoustic field of a small turbojet.- Session X — “Aeroacoustics”.- Wind tunnel investigation of aeolian tones from rough surface cylinders.- Characterising pressure fluctuations on the wall of a circular cylinder perpendicular to a flow.- Flow effects on measurement of the modal decomposition of acoustic field in a hard wall cylindrical duct.- The effects of density on subsonic jet noise.- Session XI — “Acoustics Of Unstable Flows”.- Acoustics of unstable flows.- Hydrodynamic instabilities and surface waves in a flow over an impedance wall.- Wake-induced shear layer excitation in a basic annular jet.- Transient vortex modelling of flow induced acoustic resonances near cavities or obstructions in ducts.- Etude du couplage acoustique-instabilités aérodynamiques sur une maquette de statoréacteur.- Session XII — “Flow-Acoustic Interaction”.- On the influence of opening geometry on noise from air jets.- Response of a flat plate turbulent boundary layer to intense sound waves moving in the upstream direction.- An experiment on sound turbulence interaction by impulsive sound tube.- Disturbance induced by a boundary layer on sound sources location — Application to the case of a vehicle.