I've been conducting a grid sensitivity analysis for an opened building inside a domain. I took five different grids, all structured, the meshing order was the same for all of them (meshing steps), and the reduction percentage was the same. However, the analysis didn't give a decreasing/ increasing behaviour it looked as shown; the mass flow rate percentage difference across the building relative to the inlet mass flow rate was compared for each case. which are the accurate ones? and why it is behaving like this?