Acoustic Transmission-Loss Models for a Target-Mine Simulation System (Akustiska211 Ljudutbredningsmodeller foer Studier av Sjoeminor)

摘要

Computation results are presented for shallow-water acoustic transmission loss211u001e(TL), averaged within third-octave frequency bands, for application to studies of 211u001esea mines. Two numerical computation models are utilized, both developed at FOA: 211u001ethe full-field model RPRESS and the ray model RACAUSTIC+RCLOSS. Two different 211u001etypes of environment are studied: an archipelago are with water depth 20 m and a 211u001erather soft sediment layer, and an open-water area with water depth 100 m and 211u001eharder sediments. The pressure field is computed out to a horizontal range of 250 211u001em from the mine sensor. The initial runs were made for a shallow target source at 211u001ea depth of 5 m, with the mine sensor at the bottom. Both winter and summer 211u001econditions are considered for the sound-speed profile in the water, but the 211u001edifference for the TL results at close ranges is rather small. Some complementary 211u001eruns were made for the open-water area, including ranges out to 2 km, anchored as 211u001ewell as bottom mines and deep as well as shallow targets.