Guided waves propagating in a water-filled stainless steel pipe

Nondestructive evaluation (NDE) of cylindrical pipes that carry fluid is a critical issue in the safety of nuclear power plants, pipe lines, and other similar infrastructures. The commonly used ultrasonic NDE methods that use bulk waves to inspect large areas are time-intensive, whereas NDE methods that use guided waves are not, because a guided wave has a longer propagation range. Despite this advantage, detailed clarification of the behavior of guided waves in fluid-filled cylindrical pipes has been lacking. Our previous analytical result for guided waves propagating in a fluid-filled pipe can be applied to all modes, including non-axisymmetrical modes. In this study, we compared analytical and experimental group velocities of guided waves propagating in hollow and water-filled cylindrical pipes, including non-axisymmetrical modes. Results reveal that water significantly affects group velocities and cut-off frequencies, and underscores the importance of analysis of guided waves in a fluid-filled pipe for NDE.