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Unsaturated flow (Richard's Equation) convergence issue with very dry initial condition

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Hi,

I am trying to simulate a 2D infiltration experiment on a dry homogeneous soil column. The initial volumetric water content (wc) before applying any infiltration was 0.05. To achieve this initial wc, I had to simulate a time-dependent study (study 1) with initial pressure values assigned as -1500000 Pa. All the details (i.e., model geometry, variables, and boundary conditions) can be found in the attached model file. Now, when I am applying inflow at the top boundary in the second time-dependent study (in which the initial values of variables solved for and not solved for are assigned as the last value obtained from the solution of study 1), the model isn't converging. I suppose, as water starts to come into the soil the pressure becomes >=0 and COMSOL is having issues handling this large pressure gradient. I would very much appreciate if anyone could take a look at my model and suggest me anything to work it out and run.

Thank you for your time and effort. I really appreciate it.

Abdullah



0 Replies Last Post 23.03.2021, 05:38 GMT-4
COMSOL Moderator

Hello Abdullah Al Mamun

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