Re: Entropy question


Hi, Andy,



> > >Blake's theory clearly neglects dissipation,
> > ?? Clearly ?? I do not know how you have come up with that idea.
> Blake's own paper says as much: Phys Fluids 11 (1999) 1995.
>
> Page 2003: "In looking for fundamentals one should start not from Eq.
> (1)... but from the Young equation."


Read it again. That paper does not say that Blake's theory ignores
dissipation. It says that a theory of wetting statics should start from
the Young equation.

>
> And the beginning to Section 6 "The problem of modeling", Blake clearly
> states that when one viscous fluid displaces a non-viscous fluid
> (presumably referring to dynamic viscosity) then no solution to the
> Newtonian problem exists.


It is Petrov who has shown how to combine the two limiting regimes, not
Blake. I trust that by this time you have gotten hold of a paper by
Petrov.

>
> But then he continues with the Young force-balance equation, which a
> priori neglects dissipation. In addition to neglecting any line tension
> (a subject still controversial, to be sure).
>
> And in sub-part C, "the model", I really couldn't understand what he is
> trying to do, especially point (3) on page 2005. He has slip, I think,
> and that would be dissipative,


Absolutely. Any theory which describes three-phase contact line motion
is ipso facto dissipative.


Cheers,

Zigoteau.

.