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Using step function to generate mixed Cauchy boundary condition (Rainfall infiltration boundary condition)

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Hi,

I am simulating a hydraulic performance for a 1D soil layer. I am trying to model a heavy rainfall event which will generate surface flow. I assume that the water in each time step will either infiltrate into the soil or become surface runoff, which means that no ponding on the soil surface.

I have stuck with the rainfall infiltration boundary condition, I did some research, and some paper suggested that using a mixed Cauchy boundary condition, changing the boundary condition between "Inlet" and "pervious layer" based on calculated pressure on the soil surface.

However, since I am new to COMSOL, I didn't figure out how to use the step function to switch between "Inlet" and "Pervious layer" based on soil surface pressure.

I understand this is a simple problem; I appreciate if any expert in COMSOL can help me to solve this problem.

Thank you very much!!!

Kind regards, Selena


0 Replies Last Post 29.05.2019, 10:39 GMT-4
COMSOL Moderator

Hello Selena Zang

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