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