Enhanced Global Gradient Algorithm: a general formulation

The behaviour of a looped water distribution network, operating under pressure in steady flow conditions, can be modelled by imposing mass and momentum conservation. When distributed demands along the pipes are present, they tend to be represented as lumped withdrawals at the pipes ending nodes. Although such simplification preserves mass balance, it might cause significant head loss errors which may lead to inconsistent results. Giustolisi and Todini (2008) recently proposed a correction scheme within a modified Global Gradient Algorithm (GGA) under the common assumptions of Darcy-Weisbach head loss formula and pipe friction factors independent from the flow regime. This paper provides an extension of the mentioned approach to any generic monomial head loss formula, so it can be easily incorporated into existing commercial water distribution network simulators.