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Experiments with Turbulent Jets at Mach Number 0.9A systematic investigation of the structure of turbulent jets before their interaction with shock or expansion waves was undertaken during the last year. In particular compressibility and density effects in circular jets issuing in still air were investigated experimentally. Jets with nitrogen, helium, and krypton gases at 0.3, 0.6, and 0.9 Mach numbers were investigated in detail. Particle Image Velocimetry technique was developed, tested, and used to obtain qualitative information of the two-dimensional velocity field on a plane inside the flow field, which was illuminated by a laser sheet. The motion of particles was recorded by a CCD camera, which was appropriately triggered to capture two images within a fraction of a microsecond. Statistical averaging of the data at each location reduced the large amount of acquired data. It was found that the spreading rate of the jets was reduced with increased Mach numbers or increased density ratio. It was also found that decay rates of centerline Mach numbers are higher in gases with reduced density ratio. Mach number fluctuations appear to decrease with increasing Mach number of the flow. It has been proposed that the reason for this behavior is the reduction of vortex stretching activities with increased Mach number.
Document ID
20020018890
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Agui, Juan
(City Coll. of the City Univ. of New York NY United States)
Andreopoulos, Yiannis
(City Coll. of the City Univ. of New York NY United States)
Davis, David O.
Date Acquired
August 20, 2013
Publication Date
November 1, 2001
Publication Information
Publication: HBCUs/OMUs Research Conference Agenda and Abstracts
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
P9
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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