I am working on 1-D mass transient diffusion in a radial domain (spherical object) using finite volume method. My equation reads $$\frac{\partial C}{\partial t} = D\left[\frac{\partial^2 C}{\partial r^2} + \frac{2}{r}\frac{\partial C}{\partial r}\right]\, .$$
In a sense of conservative mass within the the radial domain, plus a closed BC ( constant concentration of A species on the surface), does that mean I should end up with concentration gradient among the discretized nodes? In other words, at first time step, (forward in time) for internal nodes, Should I haveget distributed concentrations that the sum of whole domaininternal nodes will give me the initial concentration on the surface?