how to perform Tim averaging of velocity for VTK file having variable number of computational cells

I have VTK output of CFD analysis and I could not perform time averaging using Temporal statistics for velocity vector components as it shows error ( the number of cells are not constant very time step). The reason that I have variable number of cells every time step is because my simulation was featured with dynamic mesh adaption. How can I do that with this ? I’m aiming to calculate turbulent kinetic energy and it needs to determined the velocity average with time for all time steps.

You could compute statistics for each timesteps and then accumulate the results manually ?

Would resampling the fields onto a static mesh work?