Modelling and validation of defects on infrasound wind-noise-reduction pipe systems

Abstract

Infrasound signals are detectable from many different sources, such as earthquakes and man-made explosions. Wind-generated turbulent noise can mask incoming infrasound signals; however, pipe-array wind-noise-reduction systems (WNRSs) have been designed to reduce the level of noise in the observed pressure time series. Given that the arrival times of the signals need to be well-known to calculate the source back azimuth and trace velocity, the response of the WNRS must be known in magnitude and phase. Previous work has been performed to optimize these systems and effectively model them. The goal of this research is to determine the effects of different defects which may occur during normal operation in typical field-experiment conditions. The models were extended to include the effects of defective systems, such as blockages or leaks. It was found that these models could effectively recreate the responses observed in an experimental setting, and several different defects were tested and are summarized in this paper.