Stability issues of concentric pipes containing steady and pulsatile flows

In this paper, we study both the static and dynamic instabilities of submerged and inclined concentric pipes conveying fluid. The governing equation for the inner tubular beam is derived under small deformation assumptions. We obtain the discretized dynamical equations using spatial finite-difference schemes. In the case of steady flow, both buckling and flutter instabilities are investigated. In the case of pulsatile flow, we compute the eigenvalues of the monodromy matrix derived from the discretized linear system with periodic coefficients, and deduce the dynamical stability information. In addition, for a special case, in which the concentric pipes have the same length, we compare the dynamic stability results with the corresponding solutions obtained with the Bolotin method. (C) 2001 Academic Press.