Accession Number:

ADA315654

Title:

Effects of Elevated Driver-Tube Temperature on the Extent of Quiet Flow in the Purdue Ludwieg Tube.

Descriptive Note:

Interim rept. Jul 94-Jul 96,

Corporate Author:

PURDUE UNIV LAFAYETTE IN

Personal Author(s):

Report Date:

1996-12-01

Pagination or Media Count:

244.0

Abstract:

Heated driver-tube air will be needed when the existing Mach-4 test section of the Purdue Quiet-flow Ludwieg tube is replaced with a Mach-6 test section. Thus, a system was developed to heat the air in the driver tube. The air was successfully heated without dramatic adverse effects on the quiet-flow performance. Measurements of the mean and fluctuating pressure were made with a Kulite pressure transducer about 10 cm downstream of the onset of uniform flow. Temperature measurements were made with thermocouples and a cold wire. In agreement with previous results, the cold-driver quiet Reynolds number was about 400,000. The quiet-length Reynolds number decreased with increasing driver-tube temperature, dropping to 380,000 at 90C and 340,000 at 140C. Thus, a nozzle wall that is colder than the gas moves transition forward on the nozzle wall. This trend agrees with Harveys 1975 observation that a heated nozzle wall delays transition. Problems with nozzle cleanliness were encountered during the heating there were also problems with maintaining a uniform driver-tube temperature due to heat transfer to the nozzle and to the unheated upstream section of the driver tube.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE