changes.mady.by.user Arthur Aslanyan (Nafta College)
Saved on Mar 23, 2019
...
\frac{\partial p}{\partial t} = \chi \, \left( \frac{\partial^2 p}{\partial r^2} + \frac{1}{r} \frac{\partial p}{\partial r} \right)
p(t = 0, {\bf r}) = p_i
p(t, r \rightarrow \infty ) = p_i
\left[ r\frac{\partial p(t, r )}{\partial r} \right]_{r \rightarrow r_w} = \frac{q_t}{2 \pi \sigma}
p_{wf}(t)= p(t,r_w ) - S \cdot r_w \, \frac{\partial p}{\partial r} \Bigg|_{r=r_w}