ADAPTIVE SYSTEM FOR THE ACTIVE SUPPRESSION OF A WIDE-BAND HYDROACOUSTIC NOISE FIELD GENERATED BY A TURBULENT JET IN A CONDUIT

An experimental investigation of an adaptive system for the active sup pression of a wideband noise field generated by a turbulent water jet in a conduit modeling a circulation loop is reported. The adaptive sup pression system has two primary sensors for the incident field, two su ppressing radiators, and two residual-field monitoring sensors. The un idirectional reception and reradiation of acoustic waves is establishe d electronically. A microcomputer-controlled digital transversal filte r functions as the adaptive unit for generation of the suppressing sig nal. Once the suppression system is activated (adapted), the total deg ree of suppression of the hydroacoustic noise field in the region past the system of suppressing radiators is 12-14 dB in the frequency band 500-2500 Hz.