Category: Science

The Reynolds equation, first derived by Osborne Reynolds in 1886, is a partial differential equation which describes the flow of a thin lubricant film between two surfaces. It is derived from the Navier-Stokes equations and is one of the fundamental equations of classical lubrication theory. The principles of the theory are derived from the observation that the lubricant can be treated as isoviscous and laminar and the fluid film is of negligible curvature. The classical Reynold’s equation can be derived from the Navier-Stokes equations and the equation of continuity under assumptions of: constant viscosity, Newtonian lubricant; thin film geometry; negligible body force; and no-slip boundary conditions.