HeadLossCalculationMethod Enumeration |
Head loss calculation methods
Namespace: DHI.Mike1D.HDParameterDataAccess
Assembly: DHI.Mike1D.HDParameterDataAccess (in DHI.Mike1D.HDParameterDataAccess.dll) Version: 19.0.0.0 (11.1.1.1111)
SyntaxMembers| Member name | Value | Description | |
|---|---|---|---|
| Classic | 0 | Method based on F.A. Engelunds energy loss formulation. See F.A. Engelund og Fl. Bo Pedersen: Hydraulik, Den Private Ingeniørfond, Danmarks Tekniske Højskole, ISBN 87-87245-64-7 (In Danish) | |
| NoHeadLosses | 1 | The third option ignores all local losses. Regardless of the shape of the outlets, geometrical set-up of the junction and distribution of flows among inlet and outlet conduits, water levels in the junction and the outlet conduit are set equal, as if there is no change of geometry and the flow conditions between the junction and outlet conduit. This literary means that this option should be applied only where there is no change in cross section. If inappropriately applied, inconsistent results may be generated. | |
| MeanEnergyApproach | 2 | The assumption applied in the MOUSE ‘standard’ solution that the water level in the manhole and all downstream water levels of the inflowing conduits are the same, often leads to overestimates of the energy loss at the inlet. In many cases, the wetted cross-section area in the inlet pipe is smaller than in the manhole, leading to almost entire loss of the kinetic energy of the incoming flows, which is not the case. This problem is reduced by applying the effective flow area in the manhole, but this is available in MOUSE only for circular pipes and for the flow-through manholes (i.e. with one pipe in- and one pipe outflow). An alternative solution is available which fully ignores the energy loss at the inlet. For a flow-through manhole, this practically means that the energy level in the manhole is set to be equal as at the downstream end of the inlet pipe. For manholes with multiple inlets, the energy level is calculated as the weighted average of the inlet flows (i.e. large flows contribute most to the energy level). Thus, in this formulation, the total loss at the manhole is concentrated computationally at the outlet, and can be fully controlled by the user. Without doubt, this approach proves valuable for some specific situations, particularly for the flow-through manholes with ‘normal’ flow conditions. However, due attention must be paid for cases with high inlet energy levels, e.g. a small pipe with high-velocity flow entering a large basin. In such a case, the energy level of otherwise still water in the basin would be calculated as equal to the energy level of the approaching flow, i.e. much higher than realistic, with erroneous results as a consequence. |
See Also