Some observations/questions from this paper:

Section 2 - Do we need to worry about magneto-rheological effects?  They state:   "Magneto-rheological effects are expected when the magnetic field is perpendicular to the vorticity, since the alignment of the magnetic momentums along the field direction prevents the rotation of the particles in the shear."

Section 3.2 - Note that their magnetic field strength is varied from 0 to 270 G.  We should compare our magnets to these values.

Section 3.3 - First full paragraph p. 68:  This is their heuristic explanation of the effect of the magnetic particles, based on dipole interaction.  I do not quite understand this, can anyone explain it to me?  It seems pretty important that we (fully) understand this argument.

One particular issue I have with this:

 - They only consider flow between meniscus and film at the bottom meniscus.  Why?  There will also be a meniscus at the top and along the sides.  Why is there no comparison between the magnetic dipole interaction energy in these menisci?  Is there some hidden assumption that the one at the bottom is the biggest?

I do not understand their notation.  What is b, the sliding length?  What does that mean?  In the second paragraph p. 68 they seem to claim that b is larger than e, and then derive their model in the limit b<<e.   ??!!?

As far as their model, very little information is given on where their equations come from.  This is a bit frustrating.  In particular, equation (1) is referenced to a PhD thesis from Paris.  The magnetic pressure does not seem to have a reference at all. 

If we can make sense of their model, it would be useful for us to just crank up the magnetic field strength and see what happens to the solution.  Does the draining reverse?  If not, something is clearly missing.  If so, is this a good first approximation at what we have seen?

Section 3.4 - They study the growth of the black film and its dependence on field strength for a perpendicular magnetic field.  They attribute the increased growth rate to the creation and upwards motion of drops of black film at the bottom meniscus (i.e. marginal regeneration).  Why do they not discuss the growth in the parallel field case?

Note that no modeling is attempted to explain the increased growth.  Although, in the conclusion...

Section 5.1 - Conclusion They claim:   "...marginal regeneration..is still poorly understood.  Here, the perpendicular magnetic field induces marginal regeneration in the meniscus.  This effect, which could be due to the development of a magnetic instability in the meniscus, remains to be investigated.  The magnetic field could then be used as an external parameter to control the nucleation of black film in order to investigate the phenomenon of marginal regeneration, which plays an important role in the stability of soap-films and foams."

I think this is exactly what we should aim to do.

They also point out the potential importance of magnetic particle concentration.  As I mentioned on the Isenberg page, I suspect this is something that can't be ignored.

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