On the Helmholtz Equation For An Acoustically Rigid Scatterer

On the Helmholtz Equation For An Acoustically Rigid Scatterer PDF Author: Ergun Ar
Publisher:
ISBN:
Category :
Languages : en
Pages : 62

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On the Helmholtz Equation For An Acoustically Rigid Scatterer

On the Helmholtz Equation For An Acoustically Rigid Scatterer PDF Author: Ergun Ar
Publisher:
ISBN:
Category :
Languages : en
Pages : 62

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Book Description


Formulas of Acoustics

Formulas of Acoustics PDF Author: F.P. Mechel
Publisher: Springer Science & Business Media
ISBN: 3662072963
Category : Technology & Engineering
Languages : en
Pages : 1197

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Book Description
This application-orientated collection of formulas has been written by applied scientists and industrial engineers for design professionals and students who work in engineering acoustics. It is subdivided into the most important fields of applied acoustics, each dealing with a well-defined type of problem. It provides easy and rapid access to profound and comprehensive information. In order to keep the text as concise as possible, the derivation of a formula is described as briefly as possible and the reader is referred to the original source. Besides the formulas, useful principles and computational procedures are given.

Regents' Proceedings

Regents' Proceedings PDF Author: University of Michigan. Board of Regents
Publisher:
ISBN:
Category :
Languages : en
Pages : 2040

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Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1278

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Coupled Boundary and Finite Element Methods for the Solution of the Dynamic Fluid-Structure Interaction Problem

Coupled Boundary and Finite Element Methods for the Solution of the Dynamic Fluid-Structure Interaction Problem PDF Author: Siamak Amini
Publisher: Springer Science & Business Media
ISBN: 3642517277
Category : Technology & Engineering
Languages : en
Pages : 116

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Book Description
This text considers the problem of the dynamic fluid-structure interaction between a finite elastic structure and the acoustic field in an unbounded fluid-filled exterior domain. The exterior acoustic field is modelled through a boundary integral equation over the structure surface. However, the classical boundary integral equation formulations of this problem either have no solutions or do not have unique solutions at certain characteristic frequencies (which depend on the surface geometry) and it is necessary to employ modified boundary integral equation formulations which are valid for all frequencies. The particular approach adopted here involves an arbitrary coupling parameter and the effect that this parameter has on the stability and accuracy of the numerical method used to solve the integral equation is examined. The boundary integral analysis of the exterior acoustic problem is coupled with a finite element analysis of the elastic structure in order to investigate the interaction between the dynamic behaviour of the structure and the associated acoustic field. Recently there has been some controversy over whether or not the coupled problem also suffers from the non-uniqueness problems associated with the classical integral equation formulations of the exterior acoustic problem. This question is resolved by demonstrating that .the solution to the coupled problem is not unique at the characteristic frequencies and that it is necessary to employ an integral equation formulation valid for all frequencies.

Acoustic Interactions With Submerged Elastic Structures: Part Iv: Nondestructive Testing, Acoustic Wave Propagation And Scattering

Acoustic Interactions With Submerged Elastic Structures: Part Iv: Nondestructive Testing, Acoustic Wave Propagation And Scattering PDF Author: Anders Bostrom
Publisher: World Scientific
ISBN: 9814493317
Category : Science
Languages : en
Pages : 506

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Book Description
This series of volumes constitutes an outstanding collection of contributions by the most active research workers in the area of acoustics and mechanics. It brings the reader up to date on the status of the various aspects of research in this field. The volumes should preserve their value for a long time, as they represent a monument to the achievements of human research capabilities in the underwater-acoustics aspects of the environment.

European Conference on Underwater Acoustics

European Conference on Underwater Acoustics PDF Author: M. Weydert
Publisher: CRC Press
ISBN: 1482286858
Category : Architecture
Languages : en
Pages : 786

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Book Description
This book represents the proceedings of the Conference on Underwater Acoustics, held in September 1992, to bring together all the various disciplines involved in a forum to present the latest research on all aspects of marine acoustics.

Airfoil Aeroacoustics, LES and Acoustic Analogy Predictions

Airfoil Aeroacoustics, LES and Acoustic Analogy Predictions PDF Author: William Roberto Wolf
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 238

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Book Description
The development of physics-based noise prediction tools for analysis of aerodynamic noise sources is of paramount importance since noise regulations have become more stringent. Direct simulation of aerodynamic noise remains prohibitively expensive for engineering problems because of the resolution requirements. Therefore, hybrid approaches that consist of predicting nearfield flow quantities by a suitable CFD simulation and farfield sound radiation by aeroacoustic integral methods are more attractive. In this work, we apply the fast multipole method (FMM) to accelerate the solution of boundary integral equation methods such as the boundary element method (BEM) and the Ffowcs Williams & Hawkings (FWH) acoustic analogy formulation. The FMM-BEM is implemented for the solution of acoustic scattering problems and the effects of non-uniform potential flows on acoustic scattering are investigated. The FMM-FWH is implemented for the solution of two and three-dimensional problems of sound propagation. The effects of flow convection and non-linear quadrupole sources are assessed through the study of sound generated by unsteady laminar flows. Finally, a hybrid methodology is applied for the investigation of airfoil noise. This study is important for the design of aerodynamic shapes such as wings and high-lift devices, as well as wind turbine blades, fans and propellers. The present investigation of airfoil self-noise generation and propagation concerns the broadband noise that arises from the interaction of turbulent boundary layers with the airfoil trailing edge and tonal noise that arises from vortex shedding generated by laminar boundary layers. Nearfield acoustic sources are computed using compressible large eddy simulation (LES) and acoustic predictions are performed by the FMM-FWH. Numerical simulations are conducted for a NACA0012 airfoil with tripped boundary layers and blunt rounded trailing edge at different Mach numbers and angles of incidence. The effects of non-linear quadrupole sources and convection are assessed. In order to validate the numerical solutions, flow simulation and acoustic prediction results are compared to experimental data available in the literature and excellent agreement is observed.

Atmospheric Acoustics

Atmospheric Acoustics PDF Author: Xunren Yang
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110311534
Category : Science
Languages : en
Pages : 392

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Book Description
This book concisely expounds the fundamental concepts, phenomena, theories and procedures in a complete and systematic sense. In this book, not only almost all the important achievements from predecessors but also the contributions from the author himself have been summed up profoundly. Starting from the derivation of fundamental equations, various classical acoustical phenomena such as reflection, refraction, scattering diffraction and absorption in atmosphere, as well as the influences of gravitation and rotation of the earth on the behaviors of different atmospheric waves including acoustic waves, have been discussed in viewpoints of wave acoustics and geometrical acoustics respectively. The recent developments of several computation methods in the field of atmospheric acoustics have been introduced in some detail. As for the application aspects, atmospheric remote sensing has been discussed from the angle of inverse problems.

Acoustic Resonance Scattering

Acoustic Resonance Scattering PDF Author: Herbert Überall
Publisher: CRC Press
ISBN: 9782881245138
Category : Science
Languages : en
Pages : 364

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Book Description
These 13 papers were part of a May 1989 symposium at the Catholic University of America, Washington, D.C., the home of much of the early theoretical and experimental work in acoustic resonance scattering. Topics include a historical survey of the development of the subject, a description of the MIIR and short- pulse methods, and new developments such as the derivation of exact acoustic background shells, application of the method of moments, and S-matrix product expansions. Annotation copyright by Book News, Inc., Portland, OR