NONLINEAR-WAVE MODULATION IN FLUID-FILLED DISTENSIBLE TUBES

The present work considers one dimensional wave propagation in an infi nitely long, straight and homogeneous nonlinear viscoelastic or elasti c tube filled with an incompressible, inviscid fluid. Using the reduct ive perturbation technique, and assuming the weakness of dissipative e ffects, the amplitude modulation of weakly nonlinear waves is examined . It is shown that the amplitude modulation of these waves is governed by a dissipative nonlinear Schrodinger equation (NLS). In the absence of dissipative effects, this equation reduces to the classical NLS eq uation. The examination of the coefficients of the dissipative and cla ssical NLS equations reveals the significance of the tube wall inertia to obtain a balance between nonlinearity and dispersion. Some special solutions of the NLS equation are given and the modulational instabil ity of the plane wave solution is discussed for various incompressible hyperelastic materials.