Before revision: where: V is velocity k is a conversion factor for the unit system (k = 1.318 for US customary units, k = 0.849 for SI units) C is a roughness coefficient R is the hydraulic radius S is the slope of the energy line (head loss per length of pipe or hf/L) The equation is similar to the Chézy formula but the exponents have been adjusted to better fit data from typical engineering situations.
After revision: (in ft/s for US customary units, in m/s for SI units)(in ft for US customary units, in m for SI units)where: V is velocity k is a conversion factor for the unit system (k = 1.318 for US customary units, k = 0.849 for SI units) C is a roughness coefficient R is the hydraulic radius S is the slope of the energy line (head loss per length of pipe or hf/L) The equation is similar to the Chézy formula but the exponents have been adjusted to better fit data from typical engineering situations.