The Kirchhoff Formulas for Moving Surfaces in Aeroacoustics - The Subsonic and Supersonic Cases PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download The Kirchhoff Formulas for Moving Surfaces in Aeroacoustics - The Subsonic and Supersonic Cases PDF full book. Access full book title The Kirchhoff Formulas for Moving Surfaces in Aeroacoustics - The Subsonic and Supersonic Cases by National Aeronautics and Space Administration (NASA). Download full books in PDF and EPUB format.
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781723445385
Category :
Languages : en
Pages : 114
Get Book Here
Book Description
One of the active areas of computational aeroacoustics is the application of the Kirchhoff formulas to the problems of the rotating machinery noise predictions. The original Kirchhoff formula was derived for a stationary surface. In 1988, Farassat and Myers derived a Kirchhoff Formula obtained originally by Morgans using modem mathematics. These authors gave a formula particularly useful for applications in aeroacoustics. This formula is for a surface moving at subsonic speed. Later in 1995 these authors derived the Kirchhoff formula for a super-sonically moving surface. This technical memorandum presents the viewgraphs of a day long workshop by the author on the derivation of the Kirchhoff formulas. All necessary background mathematics such as differential geometry and multidimensional generalized function theory are discussed in these viewgraphs. Abstraction is kept at minimum level here. These viewgraphs are also suitable for understanding the derivation and obtaining the solutions of the Ffowcs Williams-Hawkings equation. In the first part of this memorandum, some introductory remarks are made on generalized functions, the derivation of the Kirchhoff formulas and the development and validation of Kirchhoff codes. Separate lists of references by Lyrintzis, Long, Strawn and their co-workers are given in this memorandum. This publication is aimed at graduate students, physicists and engineers who are in need of the understanding and applications of the Kirchhoff formulas in acoustics and electromagnetics. Farassat, F. Unspecified Center KIRCHHOFF LAW; PIPE FLOW; SUBSONIC SPEED; AEROACOUSTICS; ELECTROMAGNETISM; SUPERSONIC FLOW; NOISE PREDICTION; DIFFERENTIAL GEOMETRY; ROTATION; ACOUSTICS...
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781723445385
Category :
Languages : en
Pages : 114
Get Book Here
Book Description
One of the active areas of computational aeroacoustics is the application of the Kirchhoff formulas to the problems of the rotating machinery noise predictions. The original Kirchhoff formula was derived for a stationary surface. In 1988, Farassat and Myers derived a Kirchhoff Formula obtained originally by Morgans using modem mathematics. These authors gave a formula particularly useful for applications in aeroacoustics. This formula is for a surface moving at subsonic speed. Later in 1995 these authors derived the Kirchhoff formula for a super-sonically moving surface. This technical memorandum presents the viewgraphs of a day long workshop by the author on the derivation of the Kirchhoff formulas. All necessary background mathematics such as differential geometry and multidimensional generalized function theory are discussed in these viewgraphs. Abstraction is kept at minimum level here. These viewgraphs are also suitable for understanding the derivation and obtaining the solutions of the Ffowcs Williams-Hawkings equation. In the first part of this memorandum, some introductory remarks are made on generalized functions, the derivation of the Kirchhoff formulas and the development and validation of Kirchhoff codes. Separate lists of references by Lyrintzis, Long, Strawn and their co-workers are given in this memorandum. This publication is aimed at graduate students, physicists and engineers who are in need of the understanding and applications of the Kirchhoff formulas in acoustics and electromagnetics. Farassat, F. Unspecified Center KIRCHHOFF LAW; PIPE FLOW; SUBSONIC SPEED; AEROACOUSTICS; ELECTROMAGNETISM; SUPERSONIC FLOW; NOISE PREDICTION; DIFFERENTIAL GEOMETRY; ROTATION; ACOUSTICS...
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 116
Get Book Here
Book Description
Author: Fabien Anselmet
Publisher: John Wiley & Sons
ISBN: 1119178401
Category : Technology & Engineering
Languages : en
Pages : 528
Get Book Here
Book Description
This didactic book presents the main elements of acoustics, aeroacoustics and vibrations. Illustrated with numerous concrete examples linked to solid and fluid continua, Acoustics, Aeroacoustics and Vibrations proposes a selection of applications encountered in the three fields, whether in room acoustics, transport, energy production systems or environmental problems. Theoretical approaches enable us to analyze the different processes in play. Typical results, mostly from numerical simulations, are used to illustrate the main phenomena (fluid acoustics, radiation, diffraction, vibroacoustics, etc.).
Author: Matthew C. M. Wright
Publisher: World Scientific
ISBN: 1860944965
Category : Science
Languages : en
Pages : 310
Get Book Here
Book Description
Based on lectures given at a one week summer school held at the University of Southampton, July 2003.
Author: T. J. Chung
Publisher: Cambridge University Press
ISBN: 1139493299
Category : Technology & Engineering
Languages : en
Pages :
Get Book Here
Book Description
The second edition of Computational Fluid Dynamics represents a significant improvement from the first edition. However, the original idea of including all computational fluid dynamics methods (FDM, FEM, FVM); all mesh generation schemes; and physical applications to turbulence, combustion, acoustics, radiative heat transfer, multiphase flow, electromagnetic flow, and general relativity is still maintained. The second edition includes a new section on preconditioning for EBE-GMRES and a complete revision of the section on flowfield-dependent variation methods, which demonstrates more detailed computational processes and includes additional example problems. For those instructors desiring a textbook that contains homework assignments, a variety of problems for FDM, FEM and FVM are included in an appendix. To facilitate students and practitioners intending to develop a large-scale computer code, an example of FORTRAN code capable of solving compressible, incompressible, viscous, inviscid, 1D, 2D and 3D for all speed regimes using the flowfield-dependent variation method is made available.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 180
Get Book Here
Book Description
Author: Marco G. Beghi
Publisher: BoD – Books on Demand
ISBN: 9533075724
Category : Technology & Engineering
Languages : en
Pages : 670
Get Book Here
Book Description
The concept of acoustic wave is a pervasive one, which emerges in any type of medium, from solids to plasmas, at length and time scales ranging from sub-micrometric layers in microdevices to seismic waves in the Sun's interior. This book presents several aspects of the active research ongoing in this field. Theoretical efforts are leading to a deeper understanding of phenomena, also in complicated environments like the solar surface boundary. Acoustic waves are a flexible probe to investigate the properties of very different systems, from thin inorganic layers to ripening cheese to biological systems. Acoustic waves are also a tool to manipulate matter, from the delicate evaporation of biomolecules to be analysed, to the phase transitions induced by intense shock waves. And a whole class of widespread microdevices, including filters and sensors, is based on the behaviour of acoustic waves propagating in thin layers. The search for better performances is driving to new materials for these devices, and to more refined tools for their analysis.
Author: Anthony Richard Pilon
Publisher:
ISBN:
Category :
Languages : en
Pages : 242
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 180
Get Book Here
Book Description
Author: Anna Schwarz
Publisher: Springer Science & Business Media
ISBN: 3642020380
Category : Technology & Engineering
Languages : en
Pages : 304
Get Book Here
Book Description
November, 2008 Anna Schwarz, Johannes Janicka In the last thirty years noise emission has developed into a topic of increasing importance to society and economy. In ?elds such as air, road and rail traf?c, the control of noise emissions and development of associated noise-reduction techno- gies is a central requirement for social acceptance and economical competitiveness. The noise emission of combustion systems is a major part of the task of noise - duction. The following aspects motivate research: • Modern combustion chambers in technical combustion systems with low pol- tion exhausts are 5 - 8 dB louder compared to their predecessors. In the ope- tional state the noise pressure levels achieved can even be 10-15 dB louder. • High capacity torches in the chemical industry are usually placed at ground level because of the reasons of noise emissions instead of being placed at a height suitable for safety and security. • For airplanes the combustion emissions become a more and more important topic. The combustion instability and noise issues are one major obstacle for the introduction of green technologies as lean fuel combustion and premixed burners in aero-engines. The direct and indirect contribution of combustion noise to the overall core noise is still under discussion. However, it is clear that the core noise besides the fan tone will become an important noise source in future aero-engine designs. To further reduce the jet noise, geared ultra high bypass ratio fans are driven by only a few highly loaded turbine stages.
