Experimental Investigation of Rocket Motor Flow-Turning Acoustic Losses.
Abstract
Results are presented of an experimental investigation of the 'flow-turning' losses associated with the injection of steady lateral flow into a rectangular duct containing longitudinal acoustic waves. Test results show the flow-turning process absorbs sound. A one-dimensional model was derived that seriously underpredicted the measured acoustic energy losses. Two-dimensional effects in the form of redistribution of the sound pressure due to refraction by the injected mean flow velocity gradients were found to be important. Measurements showed the refraction process to increase the sound pressure at the walls thereby increasing the local wall absorption. Analysis of the data indicates that part of the flow-turning absorption process takes place at the finite admittance side walls and part within the field interior. Most of the sound absorption appears to take place within the fluid interior in support of Culick's ideas, but final interpretation of the data requires the development of a two-dimensional model of the flow-turning process. The identification of the refraction process in new and may have important applications to other rocket motor stability calculations. Key concepts include sound absorption, sound attenuation, sound flow interaction, sound flow energy exchange, flow-turning acoustic losses, and combustion instability.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1984
- Accession Number
- ADA144168
Entities
People
- A. S. Hersh
- B. Walker