Acoustic Wave Propagation in Water Filled Buried Polyethylene Pipes
Axisymmetric acoustic waves propagating along buried water pipes have been investigated by FEM and experimentally. Universal dispersion relations of the fundamental mode were obtained as a function of the standard dimension ratio SDR and of the material surrounding the pipe (soil, air). At low frequency there exists little dispersion and the “dc” phase velocity of the leak noise is independent of the surrounding material. The evolution of the dispersion curves with increasing elastic modulus E of the pipe layer is presented. Simulated curves for E = 2.2 GPa showed perfect agreement with experimental data. The 2D eigenfrequencies increase in steps with increasing pipe wall elasticity, matching the analytical values in the limit of hard walls.