Next Article in Journal
Influence of Test Stand and Contact Size Sensitivity on the Friction Coefficient in Sheet Metal Forming
Next Article in Special Issue
Lubrication Performance of Engine Commercial Oils with Different Performance Levels: The Effect of Engine Synthetic Oil Aging on Piston Ring Tribology under Real Engine Conditions
Previous Article in Journal
Material Characterization and Influence of Sliding Speed and Pressure on Friction and Wear Behavior of Self-Lubricating Bearing Materials for Hydropower Applications
Previous Article in Special Issue
Influence of Slip and Lubrication Regime on the Formation of White Etching Cracks on a Two-Disc Test Rig
Article Menu
Issue 2 (June) cover image

Export Article

Open AccessArticle

Dynamical Simulations of a Flexible Rotor in Cylindrical Uncavitated and Cavitated Lubricated Journal Bearings

Department of Industrial Engineering, University of Salerno, 84084 Salerno, Italy
Department of Mechanical Engineering, Chemical and Industrial Design, Universidad Politécnica de Madrid (UPM), 28012 Madrid, Spain
Mechanical Engineering Faculty in Slavonski Brod, J. J. Strossmayer University of Osijek, HR-35000 Slavonski Brod, Croatia
Author to whom correspondence should be addressed.
Lubricants 2018, 6(2), 40;
Received: 5 February 2018 / Revised: 16 April 2018 / Accepted: 20 April 2018 / Published: 25 April 2018
(This article belongs to the Special Issue Tribology of Machine Elements--Smart Lubricants)


Due to requirements of their operating conditions, such as high speed, high flexibility and high efficiency, rotating machines are designed to obtain larger operating ranges. These operating conditions can increase the risk of fluid-induced instability. In fact, the presence of non-linear fluid forces when the threshold speed is overcome by the rotational speed, can generate rotor lateral self-excited vibrations known as “oil whirl” or “oil whip”. These instabilities derive from the interaction between the rotor and the sliding bearing and they are typically sub-synchronous and they contribute to eventual rubbing between rotor and stator with consequent damage to the rotating machines. For these reasons, the aim of this paper is to numerically investigate the differences in the dynamic behaviour of a flexible rotor supported by cylindrical lubricated journal bearings. The study considers two different cases, uncavitated and cavitated lubricated films, in order to develop an original Matlab-Simulink algorithm for the numerical solution of the differential non-linear equations of motion of the unbalanced flexible rotor supported on hydrodynamic journal bearings. The bearings were modelled as uncavitated and cavitated (π-Film) short bearings derived from classical Reynolds’ theory. Dynamic simulation allowed prediction of the shape and size of the orbit performed by the system and evaluation of the vibrating phenomena exerted by the rotor during the motion. The results show that cavitation completely modifies the behaviour of the system in every aspect. The analysis of the diagrams obtained showed that the proposed algorithm provides consistent results and represents a valuable instrument for dynamic analysis of rotating systems. View Full-Text
Keywords: rotor dynamics; journal bearing; cavitation; Matlab-Simulink algorithm rotor dynamics; journal bearing; cavitation; Matlab-Simulink algorithm

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Ruggiero, A.; D’Amato, R.; Magliano, E.; Kozak, D. Dynamical Simulations of a Flexible Rotor in Cylindrical Uncavitated and Cavitated Lubricated Journal Bearings. Lubricants 2018, 6, 40.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Lubricants EISSN 2075-4442 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top