Accession Number : AD0782100

Title :   Diffusion from a Periodically Heated Line-Source Segment and Its Application to Measurements in Turbulent Flows.

Descriptive Note : Scientific rept.,

Corporate Author : ILLINOIS INST OF TECH CHICAGO DEPT OF MECHANICS MECHANICAL AND AEROSPACE ENGINEERING

Personal Author(s) : Wigeland,Roald A. ; Nagib,Hassan M.

Report Date : MAY 1974

Pagination or Media Count : 109

Abstract : A heat tracer technique for determination of mean streak lines and average convection velocities over long distances in turbulent flow fields is developed. The system is made up of a periodically heated line-source segment, a temperature sensing cold-wire probe, and associated signal processing equipment. Cross-correlations between the heating signal and the cold-wire output enhance resolution and permit mean velocity measurements. To evaluate the size of the thermal wake at different downstream locations and to determine the decay rate of the wake centerline temperature, a study of the diffusion of heat from the line-source segment was performed in three test flow conditions with different free-stream turbulence intensities.

Descriptors :   *Turbulent flow, *Curved profiles, *Tracer studies, *Convection(Heat transfer), Flow fields, Heat, Wake, Statistical distributions, Diffusion, Heaters, Velocity, Periodic variations, Temperature, Test methods, Attrition, Detectors

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE