Numerical Simulation of the Turbulent Flow in Ultra-Precision Aerostatic Bearings

In this paper, the transient turbulent flow field in ultra-precision aerostatic bearings is numerically investigated, with the focus on vortex structures and pressure distribution in the bearing clearance. In order to capture details of transient turbulent flow, large eddy simulation (LES) is employed. It is found that with the increase of air supply pressure, the flow in the recess becomes turbulent and vortex shedding occurs near the orifice outlet. It is also demonstrated that this unsteady vortex shedding results in pressure fluctuation in the bearing clearance, which is related to the experimentally observed small vibration of the bearing on the order of nanometers.