NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
The acoustic characteristics of turbomachinery cavitiesInternal fluid flows are subject not only to self-sustained oscillations of the purely hydrodynamic type but also to the coupling of the instability with the acoustic mode of the surrounding cavity. This situation is common to turbomachinery, since flow instabilities are confined within a flow path where the acoustic wavelength is typically smaller than the dimensions of the cavity and flow speeds are low enough to allow resonances. When acoustic coupling occurs, the fluctuations can become so severe in amplitude that it may induce structural failure of engine components. The potential for catastrophic failure makes identifying flow-induced noise and vibration sources a priority. In view of the complexity of these types of flows, this report was written with the purpose of presenting many of the methods used to compute frequencies for self-sustained oscillations. The report also presents the engineering formulae needed to calculate the acoustic resonant modes for ducts and cavities. Although the report is not a replacement for more complex numerical or experimental modeling techniques, it is intended to be used on general types of flow configurations that are known to produce self-sustained oscillations. This report provides a complete collection of these models under one cover.
Document ID
19950022299
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Lucas, M. J. (Wyle Labs., Inc. Arlington, VA, United States)
Noreen, R. (Wyle Labs., Inc. Arlington, VA, United States)
Southerland, L. D. (Wyle Labs., Inc. Arlington, VA, United States)
Cole, J., III (Cambridge Acoustical Associates, Inc. Cambridge, MA., United States)
Junger, M. (Cambridge Acoustical Associates, Inc. Cambridge, MA., United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1995
Publication Information
Publisher: NASA
Subject Category
Aerodynamics
Report/Patent Number
M-778
NAS 1.26:4671
NASA-CR-4671
Accession Number
95N28720
Funding Number(s)
CONTRACT_GRANT: NAS8-37360
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available