Open boundary "imposevelocity" problem
We are modeling the entrance chamber to a sewage pumping station (on a reduced scale 1 in 10)
The model has a single entry, defined as a boundary condition with imposed and fixed velocity (imposevelocity mode=”0”)
It has 6 outputs (one for each active pump) that are represented as free discharges to the atmosphere
My problem is that inlet velocity, and therefore the flow, does not remain constant throughout the simulation but decreases
Below is the velocity as a function of time at several points of a cross section of the inlet pipe, sufficiently far from the boundary condition
Unlike the solved examples of the library, in this case the boundary condition is completely submerged and the water level in the chamber is higher.
How can I solve this unwanted variation in the inlet velocity, which should be fixed?
I attach files so you can check