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Acoustic radiation from two-dimensional rectangular cutouts in aerodynamic surfaces / by K. Krishnamurty.

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Format:
Book
Government document
Author/Creator:
Karamcheti, Krishnamurty, author.
Contributor:
United States. National Advisory Committee for Aeronautics, issuing body.
Series:
Technical note (United States. National Advisory Committee for Aeronautics) ; 3487.
Technical notes / National Advisory Committee for Aeronautics ; No. 3487
Language:
English
Subjects (All):
Aerodynamics.
Air flow.
Surfaces (Physics).
Holes.
Sound--Measurement.
Sound.
Optical interferometers.
Interferometry.
Schlieren methods (Optics).
Hot-wire anemometer.
aerodynamics.
Physical Description:
1 online resource (33 pages) : illustrations.
Place of Publication:
Washington, [D.C.] : National Advisory Committee for Aeronautics, 1955.
Summary:
Subsonic and supersonic flow of air past rectangular cavities cut into a flat surface were studied. The cavities were found to emit a strong acoustic radiation. These acoustic fields were investigated by means of schlieren observation, interferometry, and hot-wire anemometer.
The frequency of the sound, as measured by a hot-wire, at a fixed depth of the gap was found to be inversely proportional to the breadth. No simple relationship was noticed between the Mach number M(infinity) and a nondimensional frequency S based on the gap breadth and the freestream velocity.
The intensity of the radiation was conveniently measured by means of an optical interferometer of the Mach-Zehnder type. At a Mach number of 0.8, a unit fringe shift was found to correspond to an intensity level of 160 decibels. Fringe shifts equal to and greater than 1 were observed for the radiations from these cavities, indicating that the acoustic fields were very intense.
Notes:
Title from title screen (viewed March 7, 2019).
"August 1955."
"California Institute of Technology."
No Federal Depository Library Program (FDLP) item number.
Includes bibliographical references (page 15).
Electronic reproduction. Denton, Texas : University of North Texas, 2011 Electronic reproduction from print master produced by University of North Texas
Other Format:
Paper version: Karamcheti, Krishnamurty, Acoustic radiation from two-dimensional rectangular cutouts in aerodynamic surfaces
OCLC:
1100474424

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