Interaction Between Air Flow and Airborne Sound in a Duct

Interaction Between Air Flow and Airborne Sound in a Duct
Author: Fridolin P. Mechel
Publisher:
Total Pages: 64
Release: 1965
Genre: Air ducts
ISBN:

Several studies of the interaction between air flow and airborne sound in a duct were made. Three projects were investigated: (1) The excitation of boundary layer distortions in a laminar boundary layer by simulated oscillatory flexural waves was investigated. Results show boundary layer waves are excited whenever the phase velocity of the flexure wave is in the instability range of the phase velocity of boundary layer waves. (2) The propagation of a pressure pulse wave front and the acoustic impedance of porous absorbers are examined in ducts with air flow. Measurements prove the sound energy of the wave front is directed towards the walls and the absorber impedance becomes nonlinear when the absorber is penetrated by the flow. (3) the effect on the acoustic radiation impedance of an orifice with flow discharge restricted by fences and diaphragms was investigated. The acoustic resistance was shown to increase at low frequencies due to the restrictions.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports
Author:
Publisher:
Total Pages: 1126
Release: 1987
Genre: Aeronautics
ISBN:

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Building Acoustics and Vibration

Building Acoustics and Vibration
Author: Osama A B Hassan
Publisher: World Scientific Publishing Company
Total Pages: 972
Release: 2009-06-24
Genre: Architecture
ISBN: 9813107413

As a comprehensive reference dedicated to sound and vibration in buildings, Building Acoustics and Vibration addresses the basic and advanced principles that can be used to solve practical and theoretical problems typically encountered in building and architectural acoustic practices. In addition, physical and mathematical concepts are introduced and developed sufficiently to make this publication a self-contained and up-to-date source of information for readers. Building Acoustics and Vibration is a must-have textbook for engineering students, engineers, and consultants involved in the sound, vibrations and building environment. With comprehensibility and versatility in the presentation of knowledge, this highly anticipated publication will easily fill the gap in the literature of building engineering and sciences, which presently lacks an authoritative guide on the theoretical and practical aspects of building acoustics and vibration.

Aeronautical Engineering

Aeronautical Engineering
Author:
Publisher:
Total Pages: 446
Release: 1984
Genre: Aeronautics
ISBN:

A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).