## Tori of prescribed mean curvature and the rotating drop.(English)Zbl 0581.76108

Variational methods for equilibrium problems of fluids, Meet. Trento/Italy 1983, Astérisque 118, 167-179 (1984).
[For the entire collection see Zbl 0544.00035.]
The author considers a fluid body rotating with constant angular velocity $$\omega$$ and subject to surface tension. The gravity is either absent or has net effect. The mean curvature H of the surface of a fluid drop is given by (*) 2H$$=dv/dr+v/r$$, where $$v=du/ds,\quad z=u(s),\quad r=r(s)$$ are equations for a surface of revolution in cylindrical coordinates (r,$$\theta$$,z) and s is an arclength parameter along the generating curve. The mathematical treatment of the rotating drop is based on the equation (*) and on the theory of elliptic integrals. It is shown that a large family of rotationally symmetric toroidal rotating drops exists and estimates on the possible rates of rotation are derived. The question of stability was not discussed.
Reviewer: A.V.Fedorov

### MSC:

 76T99 Multiphase and multicomponent flows 34A12 Initial value problems, existence, uniqueness, continuous dependence and continuation of solutions to ordinary differential equations

Zbl 0544.00035