Compute head loss caused by elbows, valves and other fittings from the minor loss coefficient K, flow velocity v and gravity using h = K·v²/(2g), for summing system resistance and sizing required pump head.
输入局部阻力系数 K、流速 v、g，求水头损失。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Minor loss head | h_j = ζ·v²/(2g) | Darcy-Weisbach minor-loss form |
| Loss coefficients | ζ from experiments (bends, valves) | Idelchik, Handbook of Hydraulic Resistance |