Measurements of the average properties of a suspension of bubbles rising in a vertical channel

By Roberto Zenit, D. Koch, A. Sangani. Journal of Fluid Mechanics, 2001

168 citations recorded by the source corpus.

Experiments were performed in a vertical channel to study the behaviour of a monodisperse bubble suspension for which the dual limit of large Reynolds number and small Weber number was satisfied. Measurements of the liquid-phase velocity fluctuations were obtained with a hot-wire anemometer. The gas volume fraction, bubble velocity, bubble velocity fluctuations and bubble collision rate were measured using a dual impedance probe. Digital image analysis was performed to quantify the small polydispersity of the bubbles as well as the bubble shape. A rapid decrease in bubble velocity with bubble concentration in very dilute suspensions is attributed to the effects of bubble–wall collisions. The more gradual subsequent hindering of bubble motion is in qualitative agreement with the predictions of Spelt & Sangani (1998) for the effects of potential-flow bubble–bubble interactions on the mean velocity. The ratio of the bubble velocity variance to the square of the mean is O(0.1). For these conditions Spelt & Sangani predict that the homogeneous suspension will be unstable and clustering into horizontal rafts will take place. Evidence for bubble clustering is obtained by analysis of video images. The fluid velocity variance is larger than would be expected for a homogeneous suspension and the fluid velocity frequency spectrum indicates the presence of velocity fluctuations that are slow compared with the time for the passage of an individual bubble. These observations provide further evidence for bubble clustering.

Subfields: Biomedical Engineering, Computational Mechanics, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/4a66d3d2021b0dc6576963287944dc1fbb416cc4

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Biomedical Engineering

In Computational Mechanics

In Water Science and Technology

Citations in the corpus

Experimental determination of the drag coefficient in a swarm of bubbles (2007, background): “This means that for loc< crit , measurements integrate the well-known hindrance effect caused by the presence of other bubbles in the surrounding (Ishii and Zuber, 1979; Kashinsky and Timkin, 1999; Zenit et al., 2001; Garnier et al., 2002; Guet et al., 2004).”
Dynamics of homogeneous bubbly flows Part 1. Rise velocity and microstructure of the bubbles (2002, background): “Zenit et al. (2001) found that some horizontal clustering occurs in experiments with bubbles at Reynolds number about 300, but not to the extent predicted by potential flow theory.”
Experimental characterization of the agitation generated by bubbles rising at high Reynolds number (2009, background): “Zenit et al. (2001) considered bubbles of d = 1.4mm rising in water.”
Frictional drag reduction by bubble injection (2014, unknown): “In vertical channel flows, local bubble clustering and its effect on near-wall turbulence was analyzed by Zenit et al. (2001) for spherical bubbles, and by Bunner and Tyggvason (2003) and Lu and Tryggvason (2007) for softly deformable bubbles.”