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Media type:
E-Article
Title:
Dynamics of homogeneous bubbly flows
Part 2. Velocity fluctuations
Contributor:
BUNNER, BERNARD;
TRYGGVASON, GRÉTAR
Published:
Cambridge University Press (CUP), 2002
Published in:
Journal of Fluid Mechanics, 466 (2002), Seite 53-84
Language:
English
DOI:
10.1017/s0022112002001180
ISSN:
0022-1120;
1469-7645
Origination:
Footnote:
Description:
Direct numerical simulations of the motion of up to 216 three-dimensional buoyant bubbles in periodic domains are presented. The bubbles are nearly spherical and have a rise Reynolds number of about 20. The void fraction ranges from 2% to 24%. Part 1 analysed the rise velocity and the microstructure of the bubbles. This paper examines the fluctuation velocities and the dispersion of the bubbles and the ‘pseudo-turbulence’ of the liquid phase induced by the motion of the bubbles. It is found that the turbulent kinetic energy increases with void fraction and scales with the void fraction multiplied by the square of the average rise velocity of the bubbles. The vertical Reynolds stress is greater than the horizontal Reynolds stress, but the anisotropy decreases when the void fraction increases. The kinetic energy spectrum follows a power law with a slope of approximately −3.6 at high wavenumbers.