Modelling of linear wave propagation in spatial fluid filled pipe systems consisting of elastic curved and straight elements

This paper is concerned with the theoretical analysis of time harmonic dynamics of compound elastic pipes with and without internal fluid loading. Compound pipes are assembled as a sequence of segments, each of which has a constant curvature. As a prerequisite for the wave propagation analysis, dispersion equations are solved, Green’s matrices are formulated and Somigliana’s identities are derived for an isolated curved segment. The governing equations of wave motion of a compound pipe are obtained as an ensemble of the boundary integral equations for individual segments and the continuity conditions at their interfaces. The proposed methodology is validated in several benchmark problems and then applied for analysis of the periodicity effects. The results obtained for piping systems with a variable number of identical curved segments are put into the context of the classical Floquet theory. Brief parametric studies suggest that the curved inserts can be employed as a tool for the passive control of wave propagation in fluid-filled pipes, and their stop band characteristics may be tailored to reach desirable attenuation levels in prescribed frequency ranges.