Lubrication performance of short journal bearings considering the effects of surface roughness and magnetic field

► The ferrofluids lubrication was studied considering the effects of roughness and magnetic field. ► As the magnetic increases, the coupled effects on the hydrodynamic pressure become apparent. ► The longitudinal roughness can generate stronger hydronynamic lift in short journal bearing case. ► As the length-to-diameter ratio increases, the transverse roughness becomes dominant. ► The results provide the appropriate selection and balance between these two factors.