Flow mechanism of pneumatic hammer in aerostatic bearings.

This article focuses on investigating the pneumatic hammer mechanisms in aerostatic bearings through numerical simulation and modal analysis. Using a combination of large eddy simulation (LES), dynamic mesh method (DMM), and proper orthogonal decomposition (POD), the study analyzes unsteady flow fields within the bearing recess under different excitation frequencies (10, 100, and 1000 Hz). Results reveal that vortex structures within the recess undergo a "generation–merger–fragmentation" cycle during each excitation period, with large-scale vortices dominating the pneumatic hammer phenomenon and small-scale vortices contributing to harmonic frequency components. The study finds that increasing excitation frequency amplifies load capacity fluctuations, enhances large-scale vortex prominence, and intensifies nonlinear effects, leading to more pronounced harmonic frequencies and increased energy in corresponding flow modes.