Turbulence bubble tracking

An example rather than linking average bubble size to just or essentially the (overall) power input of a particular vessel-impeller combination, dedicated CFD (preferably DNS and LES) allows for studying ( tracking ) the response of bubble size to local and spatial variations in the turbulence levels in a stirred vessel. In this way, the validity of certain modeling assumptions may be affirmed or disproved. Particularly, effects of spatial variations in e which... 

An extended version of the hybrid technique of PIV/LIF/SIT is reported by Kitagawa et al. (2005), in which the PTV technique is employed to measure the velocity field in liquid phase and track the velocity distribution of dispersed bubbles, in addition to the SIT measurement of bubbles shape and location in a microbubble-laden turbulent channel flow. It is well known that microbubbles injected into the turbulent boundary layer developing on a solid wall have a significant skin friction reduction effect. To investigate the interactions between the injected microbubbles (the void fraction is actually low but... 

Rodrfguez-Rodrfguez J, Martmez-Bazan C, Montaiies JL (2003) A novel particle tracking and break-up detection algorithm application to the turbulent break-up of bubbles. Meas Sci Technol 14(8) 1328-1340... 

The added mass and pressure gradient terms in Eq. (14) has the same form as that predicted by potential flow theory (see, e.g.. Ref. 142). Therefore these terms do not require modification. Finally, Odar [143] reported results for the memory term for rigid spheres at large Reynolds numbers. Thus one can develop an approximate equation of bubbles that should be reasonable for bubbles that are not highly deformed and which have Reynolds numbers that are O(IO ). Such an approach could, for example, be used to track small bubbles in turbulent channels or stirred tanks. 

S-6.2.6 Particle Tracks. Whenever the discrete phase model is used (Section 5-2.2.2), particle tracks can be used to illustrate the trajectories of the particles, bubbles, or droplets. Trajectories can usually be displayed in a number of ways. For example, lines can be colored by the time of the trajectory or temperature of the particle itself. In addition to lines, ribbons and tubes can generally be used. The tracks can be computed and displayed using the mean fluid velocities, or in the case of turbulent flows, using random fluctuations in the mean fluid velocities as well. These stochastic tracks often give a more realistic picture of the extent to which the particles reach all comers of the solution domain than do tracks computed from the mean velocities alone. 

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