Peculiarities of anisotropic ultrasonic transmission passage in deep sea water areas

Abstract

It is necessary to solve the problem of transmitting to the operator the information received by the underwater dosimetric complex within the framework of the works devoted to estimations of radioactive contamination of the bottom surface of deep sea areas. The use of standard radio channel in such conditions is impossible, therefore it is expedient to use ultrasonic channel of information transmission. Thus, the issue of ultrasonic anisotropic radiation transmission in deep sea water area is considered. Anisotropy of radiation is necessary to reduce the error and increase the reliability of information transmission. A boundary value problem to estimate the ultrasound pressure on the aquatic medium is formulated and its solution in the form of a wave equation in seawater is given. Attention is paid to such characteristics of sea water areas as water salinity, liquid column pressure determining its density, temperature, range of radiation propagation taking into account its frequency characteristics. The problem is solved by the known method of separation of varia­bles in spherical geometry taking into account the anisotropy of radiation, the given characteristics of which are determined on the basis of the optimal choice of the radiation direction to the ultrasonic buffer device located on the water surface of the water area, determined experimentally. The calculation results show that at the radiation frequency of 1 kHz the detector reliably registers the signal at a distance of ~ 1 km. As the frequency increases, the signal is noticeably absorbed and at a radiation frequency of ~ 40 kHz begins to fall sharply from a distance of ~ 20 m. Similar results are obtained when the problem is solved in the form of radiation of a wide beam. The results of solving the problems allow to formulate certain requirements for the design of ultrasonic detectors used for underwater transmission of information, which will make it possible to implement the method of information transmission from deep water areas when using an underwater dosimet­ric complex and, in addition, to develop a sound method of communication in deep water areas, which will play a significant role in solving the problems of information transmission in these specific condi­tions.

Keywords

• морские акватории
• подводный дозиметрический комплекс
• буферное устройство
• свойства ультразвука
• соленость морской воды
• частота излучения
• краевые задачи
• сферическая геометрия.