Construction of asymptotic solutions to conjugation problems

A steady-state mass transfer problem related to underground storage of radioactive and chemical wastes is used to illustrate the application of an approximate method that opens up new opportunities for underground thermohydrodynamic simulation. The problem is represented as a sequence of mixed conjugation problems for the expansion coefficients, the remainder term, and the boundary-layer functions. Analytical expressions for the zero- and first-order expansion coefficients are derived.