I want to solve an equation
$\frac{\partial f(p,t)}{\partial t} + {\bf{v}} \nabla f(p,t) -\frac{1}{3} \nabla . {\bf{v}} p \frac{\partial f}{\partial p} - \frac{A}{p^2} \frac{\partial}{\partial p}(p^4 f)= 0$ where $v$ is velocity. I want to solve it for a cylinder one end is fixed and other end is expanding.
\cdotfor the dot product. Is $v$ volume (wouldn't that then be a real-valued function of time)? – bgins Mar 28 '12 at 17:12