Convergence problems for values ​​of n greater than 2.5

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renaudj
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Joined: Fri Apr 26, 2024 3:19 pm
Location: Chile

Convergence problems for values ​​of n greater than 2.5

Post by renaudj » Sat Apr 26, 2025 2:17 am

Hello, nice to meet you. I've been working with multiple soil properties, varying the bulk density of the samples and therefore changing the soil hydraulic parameters. I am working with the van Genuchten-Mualem hydraulic model, the single porosity model. However, I've been experiencing convergence issues for values ​​of n [-] greater than 2.5, for example. Could you give me some insight or comment on the reason for this problem? Thank you.

Best regards

Jorge R.

Jirka
Posts: 6253
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Convergence problems for values ​​of n greater than 2.5

Post by Jirka » Sat Apr 26, 2025 4:44 am

High values of n (typical for sandy soils) make the soil hydraulic properties highly nonlinear, with sharp moisture fronts and low water retention (the residual water content is reached for low pressure heads). This typically requires finer spatial and temporal discretization, and using lower values for hCritA and the wilting point (for root water uptake). J.

renaudj
Posts: 4
Joined: Fri Apr 26, 2024 3:19 pm
Location: Chile

Re: Convergence problems for values ​​of n greater than 2.5

Post by renaudj » Sun Apr 27, 2025 8:51 pm

Thank you very much, Jirka. Problem solved. Best regards and success.

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