New Computational Methods for the Prediction and Analysis of Helicopter Noise PDF Download
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Author: Roger C. Strawn
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 18
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Book Description
Abstract: "This paper describes several new methods to predict and analyze rotorcraft noise. These methods are: 1) a combined computational fluid dynamics and Kirchhoff scheme for far-field noise predictions, 2) parallel computer implementation of the Kirchhoff integrations, 3) audio and visual rendering of the computed acoustic predictions over large far-field regions, and 4) acoustic tracebacks to the Kirchhoff surface to pinpoint the sources of the rotor noise. The paper describes each method and presents sample results for three test cases. The first case consists of in-plane high-speed impulsive noise and the other two cases show idealized parallel and oblique blade-vortex interactions. The computed results show good agreement with available experimental data but convey much more information about the far-field noise propagation. When taken together, these new analysis methods exploit the power of new computer technologies and offer the potential to significantly improve our prediction and understanding of rotorcraft noise."
Author: Roger C. Strawn
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 18
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Book Description
Abstract: "This paper describes several new methods to predict and analyze rotorcraft noise. These methods are: 1) a combined computational fluid dynamics and Kirchhoff scheme for far-field noise predictions, 2) parallel computer implementation of the Kirchhoff integrations, 3) audio and visual rendering of the computed acoustic predictions over large far-field regions, and 4) acoustic tracebacks to the Kirchhoff surface to pinpoint the sources of the rotor noise. The paper describes each method and presents sample results for three test cases. The first case consists of in-plane high-speed impulsive noise and the other two cases show idealized parallel and oblique blade-vortex interactions. The computed results show good agreement with available experimental data but convey much more information about the far-field noise propagation. When taken together, these new analysis methods exploit the power of new computer technologies and offer the potential to significantly improve our prediction and understanding of rotorcraft noise."
Author: R. Biswas
Publisher:
ISBN:
Category :
Languages : en
Pages : 11
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Book Description
Author:
Publisher:
ISBN:
Category : Military research
Languages : en
Pages : 380
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Book Description
Professional publication of the RD & A community.
Author:
Publisher:
ISBN:
Category : Military research
Languages : en
Pages : 64
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Book Description
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 388
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Book Description
Author: Ronald G. Schlegel
Publisher:
ISBN:
Category :
Languages : en
Pages : 82
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Book Description
A computer program for rotational noise prediction is documented. The program was developed as a part of a study to develop more accurate methods for predicting rotational noise levels under conditions of nonuniform inflow over the rotor disc. The computer program will calculate the root-mean-square sound pressure level for up to the 10th harmonic of rotor noise at any field point in the near or far field outside of the rotor disc. Noise levels can be calculated either from a rectangular chordwise distribution of pressure or from the measured chordwise distribution. Although the report concentrated on a helicopter rotor, the analytical results are applicable to propellers in general. (Author).
Author: American Helicopter Society
Publisher:
ISBN:
Category : Helicopters
Languages : en
Pages : 344
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Book Description
Author:
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 622
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Book Description
Author: Tarit Bose
Publisher: Springer Science & Business Media
ISBN: 1461450195
Category : Technology & Engineering
Languages : en
Pages : 175
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Book Description
Aerodynamic Noise extensively covers the theoretical basis and mathematical modeling of sound, especially the undesirable sounds produced by aircraft. This noise could come from an aircraft’s engine—propellers, fans, combustion chamber, jets—or the vehicle itself—external surfaces—or from sonic booms. The majority of the sound produced is due to the motion of air and its interaction with solid boundaries, and this is the main discussion of the book. With problem sets at the end of each chapter, Aerodynamic Noise is ideal for graduate students of mechanical and aerospace engineering. It may also be useful for designers of cars, trains, and wind turbines.
Author: Tuomas Virtanen
Publisher: Springer
ISBN: 331963450X
Category : Technology & Engineering
Languages : en
Pages : 417
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Book Description
This book presents computational methods for extracting the useful information from audio signals, collecting the state of the art in the field of sound event and scene analysis. The authors cover the entire procedure for developing such methods, ranging from data acquisition and labeling, through the design of taxonomies used in the systems, to signal processing methods for feature extraction and machine learning methods for sound recognition. The book also covers advanced techniques for dealing with environmental variation and multiple overlapping sound sources, and taking advantage of multiple microphones or other modalities. The book gives examples of usage scenarios in large media databases, acoustic monitoring, bioacoustics, and context-aware devices. Graphical illustrations of sound signals and their spectrographic representations are presented, as well as block diagrams and pseudocode of algorithms.
