An investigation of tank bottom leak detection using acoustic emission

Abstract

To investigate the acoustic emission (AE) bursts from leakage through a hole, experiments were conducted on a small test tank under different conditions. When neither backfill material nor air was involved, AE bursts were detected exactly at or very close to the hole. The instantaneous abrupt pressure change of fluid at the hole, frequently associated with the unsteady flow around the hole, is suggested as the origin of these AE bursts. On the other hand, the fluid-air or fluid-sand interaction can also produce AE bursts, but the occurrence sites and signal characteristics are different. Leakage at higher water level results in stronger AE bursts, and a larger leak hole produces move bursts. The leak rate alone is not a proper index as to whether AE bursts will occur or not. In many cases of the tests, the occurrence of AE bursts from leakage cannot be fully explained by the present knowledge of turbulence.