ABSTRACT
We shall conclude this article with a brief discussion of a new approach used to study foam drainage viz. the wetting of dry foam.
IV. WETTING OF DRY FOAM
A novel approach [40, 74, 75] has been used recently by some investigators to study foam drainage. One starts with a stable dry foam that has stopped draining. Liquid is then continuously fed at the top of the foam. It is seen that a well-defined moving front is established between the wet and dry regions of the foam. Interestingly, this front moves with a velocity that is proportional to the square root of the flow rate at which the liquid is fed into the foam. A brief discussion of the theory for this system is provided below. The interested reader is advised to refer to an excellent discussion provided by Verbist et al. [40].
