Wave Propagation in Fluid Loaded Thin Walled Waveguides

M. MAZZOTTI, J. CUADRA, A. KONTSOS, IVAN BARTOLI

Abstract


A mathematical formulation is presented to compute the dispersion characteristics of tubular thin walled waveguides with arbitrary shape that are in contact with perfect fluids. The wave propagation problem is described in the frequency-wavenumber domain by using a Semi-Analytical Finite Element (SAFE) formulation for the thin walled waveguide and a regularized 2.5D Boundary Element Method (BEM) for the fluid. The wave dispersive equation is obtained by imposing continuity and equilibrium conditions on the fluid-structure interface, where the generalized Snell-Descartes law is also enforced, resulting into a nonlinear eigenvalue problem in the complex axial wavenumber. Leaky and non-leaky poles are then found by means of a contour integral algorithm. Two numerical examples are finally presented in order to show the accuracy of the method, consisting in a fluid-filled pipe and an immersed tubular section of rectangular shape.

doi: 10.12783/SHM2015/113


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