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) : Munro, Scott E.

PDF Url : ADA315654

Report Date : DEC 1996

Pagination or Media Count : 244

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 Harvey's 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.

Descriptors :   *SUPERSONIC FLOW, *BOUNDARY LAYER TRANSITION, HEAT TRANSFER, PRESSURE GRADIENTS, PRESSURE TRANSDUCERS, SIGNAL TO NOISE RATIO, AIR FLOW, TURBULENT BOUNDARY LAYER, PRESSURE MEASUREMENT, FLOW FIELDS, TEMPERATURE GRADIENTS, MACH NUMBER, FLOW NOISE, FREE STREAM, THERMOCOUPLES, REYNOLDS NUMBER, SUPERSONIC WIND TUNNELS, NOZZLE GAS FLOW, HOT WIRE ANEMOMETERS, BOUNDARY LAYER FLOW, LAMINAR BOUNDARY LAYER, THERMAL INSTABILITY.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE