APPROXIMATE THEORY OF ANNULAR FLOW-INDUCED INSTABILITIES OF CYLINDRICAL-SHELLS

A study is presented of the dynamical behaviour and stability of a cylindrical shell containing and/or immersed in an axially flowing inviscid and incompressible fluid. The internal and/or external flow regions are confined by coaxially located rigid cylindrical walls. The unsteady fluid forces are derived from linearized potential flow theory and approximated by slender body theory. Shell motion is described by the semi-membrane theory of shells, which is acceptable for the lower natural frequencies of shells of medium length. The use of both of the above-mentioned theories and a travelling wave solution gives very simple estimations of critical flow velocities for divergence (buckling) of pinned-pinned shells, and similarly, the estimations of natural frequencies of shells in the case of stagnant fluid. Moreover, the solution, the solution gives a very clear picture of stability and the possibilities of bending-wave propagation along infinitely long shells. © 1993 Academic Press.