Swamee and Jain approximation to the Colebrook-White equation in SWMM 5
Note: There is a function called ForceMain in SWMM5/InfoSWMM whose purpose is to compute the Darcy-Weisbach friction factor for a force main using the Swamee and Jain approximation to the Colebrook-White equation . f = forcemain_getFricFactor(xsect.rBot, d/4.0, 1.0e12); return sqrt(f/185.0) * pow(d, (1./6.)); double forcemain_getFricFactor(double e, double hrad, double re) //// Input: e = roughness height (ft) // hrad = hydraulic radius (ft) // re = Reynolds number // Output: returns a Darcy-Weisbach friction factor // Purpose: computes the Darcy-Weisbach friction factor for a force main // using the Swamee and Jain approximation to the Colebrook-White equation. { double f; if ( re < 10.0 ) re = 10.0; if ( re <= 2000.0 ) f = 64.0 / re; else if ( re < 4000.0 ) { f = forcemain_getFricFactor(e, hrad, 4000.0); f = 0.032 + (f - 0.032) * ( re - 2000.0) / 2000.0; } else { f = e/3.7/(4.0*hrad); if ( re < 1.0e10 ) f += 5.7...