The performance of a journal bearing around a rotating shaft is a function of the following variables: Q, the rate of flow lubricating oil to the bearing in volume per unit time; D, the bearing diameter; N, the shaft speed in revolutions per minute; μ, the lubricant viscosity; ρ, the lubricant density; and σ, the surface tension of the lubricating oil. Suggest appropriate parameters to be used in correlating experimental data for such a system.