Gl. Vasconcelos, EXACT-SOLUTIONS FOR HELE-SHAW FLOWS WITH SURFACE-TENSION - THE SCHWARZ-FUNCTION APPROACH, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 48(2), 1993, pp. 180000658-180000660
An alternative derivation of the two-parameter family of solutions for
a Hele-Shaw flow with surface tension reported previously by Vasconce
los and Kadanoff [Phys. Rev. A 44, 6490 (1991)] is presented. The meth
od of solution given here is based on the formalism of the Schwarz fun
ction: an ordinary differential equation for the Schwartz function of
the moving interface is obtained and then solved.