Does the spherical form of the continuity equation serve much purpose?

Question

In what situations would it be applied?
What is the significance of the integral form used to derive it?(Mass conservation)

I'm sure there's some theoretical or "perfect" instance where it might have relevance, like how a solveable flow for the navier stokes equations is the pouiselle flow, but for a spherical flow, I don't see it. Perhaps I am being short sighted.

I'm not even sure if that first answer is serious. What is a 3 regina?

Answer 1

The continuity equation is usually the name applied to the conservation of current or quantum probability. The spherical form is useful for certain geometries; dealing with a point or 3d region that expands from a volume usually yields the spherical geometry and the equation yields the simplest form of the solution..

Answer 2

I believe he said 3d(D) region.