The area of pipe cross-section perpendicular to the pipeline axis:
Tubular pipe | A = 0.25 \, \pi \,d^2 | d | pipe diameter |
Elliptic pipe | A = 0.25 \, \pi \, d_1 \, d_2 | d_1, \, d_2 | elliptic diameters |
Square pipe | A = d_1 \, d_2 | d_1, \, d_2 | square diameters |
See Also