Impedance Characteristics of a Plane-Parallel Acoustic Waveguide with Combined Borders at Two-Frequency Acoustical Exitation

• Main Authors: Maksim Oleksiiovych Korzhyk, Serhii Viktorovych Kurdiuk, Oleksii Volodymyrovych Korzhyk
• Format: Article
• Language: English
• Published: Igor Sikorsky Kyiv Polytechnic Institute 2018-06-01
• Series: Mìkrosistemi, Elektronìka ta Akustika
• Subjects: импеданс, удельное акустическое сопротивление, двухчастотный пакет, плотность потока мощности, плотность акустической энергии
• Online Access: http://elc.kpi.ua/article/view/135928
• ISSN: 2523-4447; 2523-4455

The impedance characteristics of a waveguide with combined boundaries are considered in the propagation of a wave packet by a two-frequency signal. A plane-parallel waveguide with combined boundaries was modeled  by  a shallow sea with a bottom surface represented by an acoustically rigid boundary. The boundary between media "water-air" is an acoustically soft boundary. As a result of solving the problem of determining the acoustic impedance along the horizontal and along the vertical section of the waveguide, the main analytical expressions, which  described  propagation process in such boundary condition. For the determination of task solution was used the superposition of average values  of the oscillations  velocity components  and acoustic pressures. The problems of the formation in the waveguide average for the observation interval meanings  of power flux densities and acoustic energy densities are considered. The paper uses the proposition that the principle of superposition relative to the energy characteristics of the co-directional oscillations is not fulfilled and leads to the need to take into account alternating additives that correct the values and directions of the power fluxes. In this work, we also used information about the profiles of normal waves of vibrational velocity and pressure, and about the impossibility of creating plane waves in the waveguide of this type (even when using as a source of a flat piston) running along the waveguide axis. The features of the formation of the averages for the observation interval of the power flux densities in the sec. The aim of this work is to determine the specific acoustic impedances to normal waves propagating in a plane-parallel waveguide with combined boundaries and their effect on the main energy characteristics of an acoustic field, which excited by a two-frequency source. Under conditions of dispersion, for the low-frequency region and the first mode of the waveguide, the dependences are calculated. In paper shown the features of the impedance characteristics and their influence on the distribution along the waveguide channel average for the observation interval meanings power flux densities and acoustic energy density. In the paper also shown the dependence the impedance of a waveguide along the horizontal axis on the coordinate and on frequency values of the original packet. Bibl.12, Fig. 4