A. Acker, On the successive approximation of classical solutions for multi-surface free-boundary problems with general non-linear joining conditions, PAC J MATH, 188(1), 1999, pp. 1-51
We prove the global convergence of an analytical trial free-boundary algori
thm, called the operator method, in the context of a very large class of mu
ltiple-free-boundary problems in R-N, N greater than or equal to 2. We stud
y the general case of a finite number of annular ow-layers, having a nested
family of closed, (N - 1)-dimensional hypersurfaces as interfaces. Each in
terface is characterized by a general non-linear joining condition relating
the normal derivatives of the stream functions in the two adjoining layers
.