[Klempnerklaus]

Hello everyone,

I am currently simulating an air–water bubble column reactor using multiphaseEuler in OpenFOAM v12, and I am performing a mesh independence study.
For validation, I have an experimental dataset in which only the change in fluid height between the un-aerated and aerated column was measured. Consequently, this expansion height is my sole comparison parameter and the quantity I am focusing on in the mesh study.

To determine the surface height, I have been using isoSurface on alphaMean.water and extracting the values where alphaMean.water = 0.01 (1%).
I also examined radial velocity and phase fraction profiles across different meshes, and these profiles show very good agreement between the grids. However, the calculated surface height decreases significantly with each refinement step — by approximately 1.5 mm.

So far, I have varied the cell size from 2.0 × 2.0 mm down to 1.0 × 1.0 mm.

I would therefore like to ask if anyone has suggestions or alternative approaches for evaluating the expansion height in OpenFOAM v12.

Many thanks in advance and best regards,

Timo