changes.mady.by.user Arthur Aslanyan (Nafta College)
Saved on Mar 23, 2019
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V_e = \pi r_e^2 h, \quad dV = 2\pi r \, h, dr
p_r = \frac{1}{V_e} \int p(r) dV = \frac{2}{r_e^2} \int p(r) \, r \, dr = \frac{2}{r_e^2} \int \bigg[ p_i - \frac{q_t}{2\pi \sigma} \ln \frac{r}{r_w} \bigg] \, r \, dr = p_i - \frac{q_t}{2\pi \sigma} \bigg[ \ln \frac{r_e}{r_w} - 0.5 \bigg]