Identification of the Place and Materials of Knocking Objects in Flow Induced Vibration

Flow induced vibration can be found and identified by acoustic methods. Using acoustic sensors, the first task, the event detection has been solved using the sequential probability ratio test after autoregressive filtering the measured signal. The LAB View program and actual test of the event recognition technique are presented. The signals were recorded in a 100 m long test loop having artificially placed flow induced vibrating objects hitting the wall. Time delay between the fronts of detected events has been used to localize the actual place of the acoustic source. The recognition of the material of the knocking object is based traditionally on the spectrum estimation. However, this is rather time consuming task by naked eyes. We are proposing to introduce the skeleton method for event identification.