The effects of interference between circular cylinders in cross flow

Abstract

One is dismayed if not surprised by the disorderly state of a topic of such practical importance. An attempt is first made to categorize various cluster arrangements in terms of the number of pipes (cylinders), their mutual spacing and orientation to the oncoming current. The second step classifies the basic interference flow regimes in the subcritical, critical and postcritical states, for two pipes only, in all possible arrangements. The third step goes further and considers various clusters and distinguishes between the basic interference flow regimes, however modified they may be, and the additional ones for particular orientations. This approach allows some qualitative interpretation and even the prediction of the forces exerted on any of the pipes in the cluster, for various orientations. The following clusters are discussed in some detail: aligned, triangular, square, staggered, all with pipes of the same size, and clusters with pipes of different diameters, i.e. small pipes arranged circumferentially around a big central one. This field is an example of ad hoc testing, leading to a proliferation of undigested and uncorrelated data.