Computes Discharge given Diameter, Material, and Head Loss using Swamee Jain (1976)
D = Pipe diameter (in feet or meters)
g = Gravitational acceleration constant (32.2 ft/s^2 or 9.8 m/s^2)
hl = Head loss (in feet or meters)
L = Pipe length (feet or meters)
ks = Equivalent sand roughness height (a material property; in feet or meters)
v = Kinematic viscosity (in feet^2/second or meter^2/second)
Notes:
Swamee and Jain, A. K., 1976. Explicit equations for pipe-flow problems.
ASCE J. of Hyd. Div., 102(HY5) pp. 657-664