1. Introduction

The analysis of dynamic properties of rotating machinery has for many years been the subject of numerous research studies carried out in many scientific centers. For modern day rotating machinery it is required to work with increasingly difficult operating parameters while maintaining a light and compact design. Increased efficiency, reliability, and precision are also required. Rotating machinery with hydrodynamic bearings is used in many sectors of the economy, e.g. energy, transport, aviation, and military. Very often they are a key element of large technical objects.