Turbulence measurements in the bubbly flow region of hydraulic jumps

Journal Article · Wed Oct 15 00:00:00 EDT 2008 · Experimental Thermal and Fluid Science

DOI:https://doi.org/10.1016/J.EXPTHERMFLUSCI.2008.06.012· OSTI ID:21116086

Kucukali, Serhat ^[1]; Chanson, Hubert ^[2]

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1. Division of Civil Engineering, Zonguldak Karaelmas University, Zonguldak (Turkey)
2. Division of Civil Engineering, The University of Queensland, Brisbane QLD 4072 (Australia)

A hydraulic jump is characterized by a highly turbulent flow with macro-scale vortices, some kinetic energy dissipation and a bubbly two-phase flow structure. New air-water flow measurements were performed in a large-size facility using two types of phase-detection intrusive probes: i.e. single-tip and double-tip conductivity probes. These were complemented by some measurements of free-surface fluctuations using ultrasonic displacement meters. The void fraction measurements showed the presence of an advective diffusion shear layer in which the void fractions profiles matched closely an analytical solution of the advective diffusion equation for air bubbles. The free-surface fluctuations measurements showed large turbulent fluctuations that reflected the dynamic, unsteady structure of the hydraulic jumps. The measurements of interfacial velocity and turbulence level distributions provided new information on the turbulent velocity field in the highly-aerated shear region. The velocity profiles tended to follow a wall jet flow pattern. The air-water turbulent integral time and length scales were deduced from some auto- and cross-correlation analyses based upon the method of Chanson [H. Chanson, Bubbly flow structure in hydraulic jump, Eur. J. Mech. B/Fluids 26 (3) (2007) 367-384], providing the turbulent scales of the eddy structures advecting the air bubbles in the developing shear layer. The length scale L{sub xz} is an integral air-water turbulence length scale which characterized the transverse size of the large vortical structures advecting the air bubbles. The experimental data showed that the dimensionless integral turbulent length scale L{sub xz}/d{sub 1} was closely related to the inflow depth: i.e. L{sub xz}/d{sub 1} = 0.2-0.8, with L{sub xz} increasing towards the free-surface. (author)

• OSTI ID: 21116086
• Journal Information: Experimental Thermal and Fluid Science, Vol. 33, Issue 1; Other Information: Elsevier Ltd. All rights reserved; ISSN 0894-1777
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
AIR
EXPERIMENTAL DATA
HYDRAULICS
LENGTH
FLUCTUATIONS
WATER
DIFFUSION EQUATIONS
TURBULENCE
SURFACES
BUBBLES
SHEAR
VELOCITY
ANALYTICAL SOLUTION
KINETIC ENERGY
TURBULENT FLOW
TWO-PHASE FLOW
VOID FRACTION
DEPTH
LAYERS
CORRELATIONS
DIFFUSION
DISTRIBUTION
JETS
VORTICES
Hydraulic jumps
Free-surface fluctuations
Turbulence
Air-water flow properties