who can help me!

I have a question related to the model i practiced. the flux boundaries conditions in saturated flow. I have performed a 3D saturated model, with lateral flux boundary ( inflow ). It is a five layers model. With a thickness of fifty meters on the border where the conditions are imposed. After simulation when I am checking the budget analyser, I notify that water is also going in and out of these boundaries ? The simulation results are not respecting the boundary restrictions ? why does water coming in and out, when inflow boundaries are imposed ? How can I manage it ?

Thank you for your help!

How do you have imposed your boundary conditions?

Hi,

the reason for that behaviour are probably model oscillations. The hydraulic head at the boundary condition oscillate and FEFLOW can not achieve the flux condition. Possible reason can be:
the water table drops below and several layer fall dry, the conductivity is reduced (only available for phreatic models)  ->you should increase the residual water depth of dry cells
in ‘free and movable’ the model thickness is changed and that caused different fluxes-->use the integral flux boundary condition instead of the normal flux boundary condition
The list of possible reason and relationships between the parameter and boundary condition is still long and it is difficult to evaluate it without the model. You can send the fem file to support@wasy.de if you can not find the exact reason.

Cheers Karsten

for first aid-
did you use the constrains?
for "flux" inflow only boundary mark the "Min" checkbox and input 0 to the box near it.