ABSTRACT
I begin this chapter with some personal remarks. I started studying Rotor Dynamics in 1961, while working at the Institute of Fundamental Technical Research of the Polish Academy of Sciences in Warsaw. Twelve years later, after having reviewed over 1000 papers and books on the subject, I published a survey paper entitled ‘‘On Rotor Dynamics’’. All topics related to rotordynamic phenomena, as well as the corresponding mathematical models, seemed quite clear and elegant to me, except for rotor/fluid interaction problems. At that time, I was unable to find a single publication, which could convince me as to the correctness of the interpretations of the physical phenomena taking place in the clearances between the rotating and stationary parts of rotor systems. Actually, at those times, the only rotor/fluid interaction systems being considered in the rotordynamics literature were fluidlubricated bearings, and most often, the model of the fluid-induced forces was simply a set of so-called ‘‘bearing coefficients’’. Even when a description of the rotor/bearing dynamic phenomena was offered, the researchers usually presented differing and confusing points of view. The complexity of these phenomena, and the large number of factors affecting them, made the picture extremely obscure. Even the names used to label these phenomena differed. The names ‘‘fluid whirl’’ and ‘‘fluid whip’’, the fluid-induced self-excited vibrations of rotors, used in this book, are ‘‘generalizations’’ of the terms, which have appeared throughout the rotordynamics literature. Among them, there were ‘‘oil film whirl’’, ‘‘oil whip’’, ‘‘resonant whip’’, ‘‘steam whirl’’, ‘‘half-speed whirl’’, ‘‘steam whip’’, ‘‘gas swirl’’, ‘‘self-excited vibrations’’, or even just ‘‘rotor instability’’. The terms ‘‘oil film whirl’’ and ‘‘oil whip’’ were introduced over 75 years ago, and in later publications were used together with other
At the time when I began the survey paper, machine monitoring was in its infancy, so that very little was generally known about measured fluid-related effects in rotating machinery behavior. Reluctantly, since I had many unanswered questions, I devoted one of the sections of this survey to the topic ‘‘Dynamics of Shafts Rotating in Plain Bearings’’.
terms (see Newkirk, 1924; Newkirk et al., 1925, 1934; Robertson, 1933; Poritsky, 1953; Sherwood, 1953; Pinkus, 1953, 1956; Tondl, 1957, 1962, 1965a, 1967a; Hori, 1959; Gunter, 1966; Elwell, 1961; Whitley, 1962; Ausman, 1963; McCann, 1963; Sternlicht, 1963; Cheng et al., 1963; Someya, 1964; Sternlicht et al., 1964; Michell et al., 1965, 1966a,b; Lund et al., 1967; Ono et al., 1968).
