“introduction:

The impetus for presenting a paper on flow-induced vibration (here forward simply referred to as `FIV’) comes from a few key observations made by the author:

The goal of this paper therefore is to offer some fundamental concepts in FIV that can help plant personnel begin to solve common problems. The focus here is on the fundamental concepts that are relevant to all plant components — machinery and fixed equipment alike, and so this paper should be useful for both machinery and fixed equipment engineers.

"Classification Of Fiv Problems:

It appears helpful to first get a handle on the wide range of problems encountered in process plants by attempting to categorize the problems in some fashion. A good classification of the subject specific to plant problems is needed – Figure 1 is one such classification. Note that other authors have presented slightly different classifications of the subject of FIV intended to cover a wider range of problems encountered in different industries and applications [2, 5]. All of the FIV problems shown in Figure 1 are discussed in this paper, with the exception of fluid shock.

"Fundamentals Of Vibration And Acoustics:

Before discussing the various sources of FIV problems, a discussion of the natural system dynamics of mechanical and fluid systems is needed. Most vibration analysts and engineers are probably more familiar with the vibration of mechanical systems rather than the vibration of fluid systems (i.e. acoustics). With any luck the following discussion will demonstrate that the two types of vibration systems are essentially identical.

Figure 2 and Figure 3 illustrate the fundamentals of vibrations and acoustics by reviewing the natural frequencies and mode shapes of simple systems. The results for natural frequency and wave speed given in Figure 2 and Figure 3 come from solutions to the wave equation [1, 4].”