Force Main Transition between Partial and Full Flow 1. If the force main is full then the program will use either Hazen-Willams or Darcy-Weisbach to calculate the friction loss (term dq1), 2. If the force main is NOT full then the program will use Manning's Equation. // --- compute terms of momentum eqn.: // --- 1. friction slope term if ( xsect->type == FORCE_MAIN && isFull ) dq1 = dt * forcemain_getFricSlope(j, fabs(v), rMid); else dq1 = dt * Conduit[k].roughFactor / pow(rWtd, 1.33333) * fabs(v); double forcemain_getFricSlope(int j, double v, double hrad) // // Input: j = link index // v = flow velocity (ft/sec) // hrad = hydraulic radius (ft) // Output: returns a force main pipe's friction slope // Purpose: computes the headloss per unit length used in dynamic wave // flow routing for a pressurized force main using either the // Hazen-Williams or Darcy-Weisbach flow equations. // Note: the pipe's roughness f