Posted Fri, 03 Nov 2006 09:46:44 GMT by andy2000
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!
Posted Tue, 14 Nov 2006 09:38:33 GMT by Thierry
How do you have imposed your boundary conditions?
Posted Tue, 09 Jan 2007 08:44:16 GMT by Karsten König

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 if you can not find the exact reason.

Cheers Karsten
Posted Wed, 10 Jan 2007 07:12:37 GMT by Denim Umeshkumar Anajwala
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.

You must be signed in to post in this forum.