yes author used fluent in the paper with pressure inlet and pressure outlet boundary conditions he fixed the inlet pressure and at 1e+07 and varies the outlet pressure between 4e+06 t0 1e+06 . i'm trying to simulate with oulet pressure at 3e+06 with k-epsilon model and non equilibrium wall function (same as in the paper) but author did not mention the turbulence specification method so i take turbulence intensity as 5% and hydraulic diameter as specification method