Experimental observations on transition to turbulence in confined coaxial jets and other boundary layer flows

Conference · Mon Jan 01 04:00:00 EST 1990

OSTI ID:7002583

Gore, R A ^[1]; Crowe, C T ^[2]; Bejan, A ^[3]

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1. Los Alamos National Lab., NM (USA)
2. Washington State Univ., Pullman, WA (USA). Dept. of Mechanical and Materials Engineering
3. Duke Univ., Durham, NC (USA). Dept. of Mechanical Engineering and Materials Science

Experiments performed demonstrate the transition to turbulent flow of water jets discharging coaxially into a stream confined in a round duct. The critical Reynolds number is shown to be a strong function of velocity ratio. From the flow visualization it is shown that a proportionality between the laminar length of the jet (L) and the wavelength ({lambda}) can be seen in the region of transition to turbulence. The proportionality coincides with similar observations concerning the transition to turbulence in various other flows. A brief argument based on scale analysis is presented for the confined coaxial jet and round plume. The apparent universality of the L/{lambda} {approximately} O(10) scaling law supports the conclusion that the laminar sections of all naturally progressing boundary layer-type flows are geometrically similar. 21 refs., 8 figs.

• Research Organization: Los Alamos National Lab., NM (USA)
• Sponsoring Organization: DOE/MA
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7002583
• Report Number(s): LA-UR-90-857; CONF-900651--2; ON: DE90008939
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
BOUNDARY LAYERS
COMPARATIVE EVALUATIONS
FLOW RATE
FLUID FLOW
LAMINAR FLOW
LAYERS
MEASURING METHODS
MIXING
NOZZLES
PERFORMANCE TESTING
PRANDTL NUMBER
REYNOLDS NUMBER
SHEAR
TESTING
TRANSITION FLOW
TURBULENCE
VARIATIONS
WAVELENGTHS