I'm writing up my final-year dissertation and I'm required to give, as part of the introduction, an analysis of all the equations (and their terms) of which I use. Embarrassingly, whilst of course understanding the principle of mass continuity, I'm not quite sure about the physical interpretation of each of the terms, $A$ and $B$.
$$\underbrace{\frac{\partial \rho}{\partial t}}_{\text{A}} + \underbrace{\nabla \cdot (\rho \textbf{v})}_{\text{B}} = 0$$
I mean, I know $A$ is the change in density w\r\t time and $B$ is the divergence (flux density) of the density $\times$ the velocity, but I don't think that's quite enough, if you follow. Any help/guidance or reading resources would be greatly appreciated.
