Accession Number:

ADP004176

Title:

Natural Unsteadiness of a Separation Bubble behind a Backward-Facing Step,

Descriptive Note:

Corporate Author:

STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING

Personal Author(s):

Report Date:

1984-01-01

Pagination or Media Count:

3.0

Abstract:

Low-frequency unsteadiness of a reattaching shear layer was studied in subsonic flow behind a backward-facing step. Power spectra of streamwise velocity fluctuations were measured using a hotwire probe. Spectra measured near the centerline of the separated shear layer showed that a substantial fraction of the measured turbulence intensity occurs at frequencies significantly lower than the large-eddy passing frequency. The strong low-large-eddy passing frequency. The strong low-frequency contribution is not present in the upstream boundary layer or in the reattached shear layer. It was concluded that the low-frequency energy is caused by a non-periodic vertical motion of the separated shear layer. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE