Accession Number:

AD0263766

Title:

EFFECTS OF MACH NUMBER, LEADING-EDGE BLUNTNESS, AND SWEEP ON BOUNDARY-LAYER TRANSITION ON A FLAT PLATE

Descriptive Note:

Corporate Author:

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON D C

Personal Author(s):

Report Date:

1961-09-01

Pagination or Media Count:

1.0

Abstract:

The effects of leading-edge bluntness and sweep on boundary-layer transition on flat plate models were investigated at Mach numbers of 2.00, 2.50, 3.00, and 4.00. The effect of sweep on transition was also determined on a flat plate model equipped with an elliptical nose at a Mach number of 0.27. Models used for the supersonic investigation had leading-edge radii varying from 0.0005 to 0.040 inch. The free-stream unit Reynolds number was held constant at 15 million per foot for the supersonic tests and the angle of attack was 0 degrees. Surface flow conditions were determined by visual observation and recorded photographically. For the models with the blunter leading edges, the transition Reynolds number based on free-stream flow conditions was approximately doubled by an increase in Mach number from 2.50 to 4.00 and nearly the same result was predicted from shock-loss considerations. At all supersonic Mach numbers, increases in sweep reduced the transition Reynolds number and the amount of reduction increased with increases in bluntness. The shock-loss method considerably underestimated the sweep effects, with swept wings. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE