Discussion Forum

Hi everyone,

I am working on a hydraulic model. The geometry of my model is shown in the attached Figure. I am using Richard's equation. There are host rock that occupies most of the model, a fault shown as the narrow pipe, and other formations at the top right.

The general water flow process is that the inflow is through the top boundary with topography and outflow is through right boundary and top boundary when water table intercepts the surface, which means that pressure head at the top is higher than zero.

For boundary conditions, a constant precipitation was applied at the top boundary with topography, which is in green in the figure. A pressure head of 0 Pa was applied at the top of fault. For the rest top part, a previous layer was applied and it will be applied a big conductance when pressure head is higher than zero. Otherwise, a conductance of 0 will be applied.

The main object of these settings was to ensure that the location of the water table can be dynamic determined by the precipitation rate and permeability instead of applying a constant head at the top.

However, when I use Time-dependent solver for cases that don't have a steady state, the solver does not converge/converges slowly. The solving progress usually stays at 4% and does not move on. If anyone has any insights about how to make it converge or improve my model, i would really appreciate it! Please let me know if more information is needed. Thank you!

Best, Zihao