EFFECT OF AN INTERNAL FLOW ON THE DISTRIBUTION OF VIBRATIONAL-ENERGY IN AN INFINITE FLUID-FILLED THIN CYLINDRICAL ELASTIC SHELL

The vibrational energy distribution in an infinite elastic cylinder with an internal uniform flow is investigated. Energy ratios between the power flow in the fluid field and the power flow in the shell are evaluated, using a fully coupled analysis, for a steel and a hard rubber shell of various thicknesses filled with convected water and vibrating in the n = 0, 1, 2 and 3 circumferential modes. The impact of the flow on the dispersion curves is first studied. The effect of the Mach number on the distribution of vibrational energies propagating upstream and downstream is then discussed, and shown to depend upon the branch behaving as either a fluid type or a structural type wave. In general, for downstream propagation, convection increases the power in the structure for structural type waves and decreases it in the structure for fluid type waves. The reverse is true for upstream propagation. Finally, the effect of the flow is shown to be greatest near coincidence or the cut-on frequencies of higher order modes. © 1993 Academic Press Limited.