[madfan123]

Hello everyone,



I have the next issue. I am using interfoam for simulation of water transport in pipelines. I've found completely different water behavior in openfoam v2.1.0 and v6 and can't find an explanation why does it happen


For example, I have water in the siphon. Upstream there is inlet. When the simulation starts air goes through the pipe and pushes water from siphon.
In v2.1.0 I can observe formation of waves and splash after that. But at the same time in v6 water interface is still smooth. Only after some delay one wave forms and only after that splash takes place. Fluid properties in both cases are identical (water + air). Mesh is identical as well. From simulation results after comparison it seems that in v6 water has higher density or viscosity than in v2.1.0, but in the settings it isn't. I attach screenshots for both openfoam versions at the different timesteps, where we can see this phenomena. My personal feeling is that in v2.1.0 water behavior is more realistic. Also I attach comparison of numerical schemes used in both simulations.

So I would appreciate any hints or recommendations which could help me to find an explanation of this difference and solve this issue.

Thank you very much in advance



Sincerely,
Yevgeniy