https://doi.org/10.1007/s100510050978
Uniform foam production by turbulent mixing: new results on free drainage vs. liquid content
UCLA, Department of Physics and Astronomy, Los Angeles, California 90095-1547, USA
Received:
15
February
1999
Published online: 15 November 1999
An apparatus is described for rapidly producing large quantities of foam
via turbulent mixing of gas with a narrow jet of a surfactant solution
inside a delivery tube. By controlling relative flow rates, the gas volume
fraction in the resulting foam may be easily varied across 
.
Using such foams, we present a comprehensive set of data for free drainage
as a systematic function of gas fraction and sample geometry. The qualitative
behavior can be understood in terms of simple theoretical considerations,
emphasizing the importance of controlling the initial foam conditions.
Quantitative features are compared with two approximate versions of the
drainage equation, highlighting the crucial role of capillarity for very
dry foams and small samples.
PACS: 82.70.Rr – Aerosols and foams / 47.60.+i – Flows in ducts, channels, nozzles, and conduits / 47.55.-t – Nonhomogeneous flows
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
