On the exact speed and amplitude of solitary waves in fluid-filled elastictubes

By casting the solitary wave problem within a variational framework, it bec omes possible to find explicit first integrals, allowing for the solution o f the exact amplitude of the wave by finding the roots of an algebraic syst em. The underlying exact membrane theory used for the tube does not impose any restrictions on the magnitude of the radial or axial displacements. It is shown that the so-called long-wave approximation is fundamentally incorr ect, even for very small wave amplitudes.