arXiv subjects

K. S. Kniazeva

Publications and source records attributed to K. S. Kniazeva.

3 recordsLinked to original sources

arXiv2021

Saddle point method for transient processes in waveguides

A modification of the saddle point method is proposed for computation of non-stationary wave processes (pulses) in waveguides. The dispersion diagram of the waveguide is continued analytically. A set of possible saddle points on the dispersion diagram is introduced. A method of checking whether the particular saddle points contribute terms to the field decomposition is proposed. A classification of the waveguides based on the topology of the set of possible saddle points is outlined.

physics.comp-ph↗

arXiv2021

Transient processes in a gas / plate structure in the case of light gas loading

Problems of pulse excitation in an acoustic waveguide with a flexible wall and in an acoustic half-space with a flexible wall are studied. In both cases the flexible wall is described by a thin plate equation. The solutions are written as double Fourier integrals. The integral for the waveguide is computed explicitly, and the integral for the half-space is estimated asymptotically. A special attention is paid to the pulse, which is a harmonic wave of a finite duration associated with the coincidence point of the dispersion diagrams of the acoustic medium and the plate. The method of estimating of the double Fourier integral is applied to the problem of excitation of waves in a system composed of an ice plate, water substrate, and the air.

physics.class-ph↗

arXiv2020

Asymptotical study of two-layered discrete waveguide with a weak coupling

A thin two-layered waveguide is considered. The governing equations for this waveguide is a matrix Klein--Gordon equation of dimension~2. A formal solution of this system in the form of a double integral can be obtained by using Fourier transformation. Then, the double integral can be reduced to a single integral with the help of residue integration with respect to the time frequency. However, such an integral can be difficult to estimate since it involves branching and oscillating functions. This integral is studied asymptotically. A zone diagram technique is proposed to represent the set of possible asymptotic formulae. The zone diagram generalizes the concept of far-field and near-field zones.

math-ph↗