[vikash0603]

Hi

I want to simulate (comsol) a transient three-phase flow in porous media considering capillary action (Filter paper soaking water up). The porous zone is initially filled with air. I want to model the displacement of air with two liquids (water and glycerin, let's say) due to capillary forces. My main interest is the degree of wetting and the spreading of the wetting front. How to model capillary effects in the porous zone? I did the simulation but It is throwing an error " Unknown function or operator, Name: step1" Can anyone help me out?

Kindly find the attachment here:https://drive.google.com/file/d/1WKVIhe7CLFmuI-YfxP8Kla_Oh0EvaAsW/view?usp=sharing

https://drive.google.com/file/d/1WKV...ew?usp=sharing