An anisothermal, compressible, piezoviscous model for journal-bearing lubrication

Compressibility plays a significant role in the load-bearing capacity of a journal bearing. This paper offers more realistic modelling of the lubricant than presented in an earlier paper (Int. J. Numer. Meth. Fluids 2007; 55(11):1091–1120) by including variable sound speed, piezoviscosity and both temperature and shear thinning. The load-bearing capacity of the journal bearing is sensitive to all of these attributes of the model, but piezoviscosity is found to be the most significant. The equations of motion are adapted to a moving frame to explore the stability of the journal in a more dynamic setting and it is found that a free journal using this model will spiral outward exhibiting half speed whirl. The model is discretized in 2D, semi-implicitly in time and using the spectral element method in space. Numerical results are presented that highlight the contributions of the different elements in the model to journal stability