The continuity equation is usually written
(1) where
is the density of the fluid at a point.
(2) or
(3) where
is the Stokes derivative.< >(2) follows from (1) on using the identity
< >To derive (3) write
Alternative Forms of The Continuity Equation
(2) or(3) where is the Stokes derivative.< >(2) follows from (1) on using the identity< >To derive (3) write