ABSTRACT
This chapter presents methods to solve problems with three independent variables involving first-order differential equations and third-kind boundary conditions. Therefore, partial differential equations are involved. Mathematically, this class of cases can be summarized as third-kind boundary condition. The chapter presents a three-dimensional (3-D) scheme for the problem of heating fluid at 2-D flow where the heat flux is given by the rate of convective transfer between the grid and the fluid. The solution is obtained by Laplace transform. The chapter also presents a 3-D scheme for the problem of reacting fluid at 2-D flow where after the component A reacts with component B, the rate of mass transfer of A by diffusion through the porous grids equals its rate of mass transfer by convection into the fluid. Here too, Laplace transform is used to obtain the solution.
