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Dynamics of homogeneous bubbly flows Part 1. Rise velocity and microstructure of the bubbles
Direct numerical simulations of the motion of up to 216 three-dimensional buoyant bubbles in periodic domains are presented. The full Navier–Stokes equations are solved by a parallelized finite-difference/front-tracking method that allows a deformable interface between the bubbles and the suspending...
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Published in: | Journal of fluid mechanics 2002-09, Vol.466, p.17-52 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that cite this one |
Online Access: | Get full text |
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Summary: | Direct numerical simulations of the motion of up to 216 three-dimensional buoyant bubbles in periodic domains are presented. The full Navier–Stokes equations
are solved by a parallelized finite-difference/front-tracking method that allows a deformable interface between the bubbles and the suspending fluid and the inclusion
of surface tension. The governing parameters are selected such that the average rise
Reynolds number is about 12–30, depending on the void fraction; deformations
of the bubbles are small. Although the motion of the individual bubbles is unsteady,
the simulations are carried out for a sufficient time that the average behaviour of
the system is well defined. Simulations with different numbers of bubbles are used to
explore the dependence of the statistical quantities on the size of the system. Examination of the microstructure of the bubbles reveals that the bubbles are dispersed
approximately homogeneously through the flow field and that pairs of bubbles tend to
align horizontally. The dependence of the statistical properties of the flow on the void
fraction is analysed. The dispersion of the bubbles and the fluctuation characteristics,
or ‘pseudo-turbulence’, of the liquid phase are examined in Part 2. |
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ISSN: | 0022-1120 1469-7645 |
DOI: | 10.1017/S0022112002001179 |