On the optimal design of pipes conveying fluid

The stability and optimal design of a beam subject to forces induced by fluid flow through attached pipes is investigated. The structure is assumed to have the same dynamics as a fluid-conveying pipe, and the dynamic stability is analysed using a finite element formulation of the linear equation of motion. The optimal design problem of minimizing the structural mass at fixed critical flow speed is solved. The numerical results are compared to experiments with satisfactory agreement, provided that the lower bounds of the beam dimensions are properly chosen. The influence of structural damping on the critical flow speed is significant, and is found to be strongly design-dependent. (C) 1998 Academic Press Limited.