Long Wave Problems in Harbours: Numerical Techniques and Boundary Conditions

The paper deals with the three-dimensional problem in linear isotropic elasticity for a coated half-space. The coating is modelled via the effective boundary conditions on the surface of the substrate initially established on the basis of an ad hoc approach and justified in the paper at a long-wave limit. An explicit model is derived for the surface wave using the perturbation technique, along with the theory of harmonic functions and Radon transform. The model consists of three-dimensional ‘quasi-static’ elliptic equations over the interior subject to the boundary conditions on the surface which involve relations expressing wave potentials through each other as well as a two-dimensional hyperbolic equation singularly perturbed by a pseudo-differential (or integro-differential) operator. The latter equation governs dispersive surface wave propagation, whereas the elliptic equations describe spatial decay of displacements and stresses. As an illustration, the dynamic response is calculated for impulse and moving surface loads. The explicit analytical solutions obtained for these cases may be used for the non-destructive testing of the thickness of the coating and the elastic moduli of the substrate.

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Use of the pass-through method to solve sound radiation problems of a spherical electro-elastic source of zero order

EUREKA Physics and Engineering ◽

10.21303/2461-4262.2021.001292 ◽

2021 ◽

pp. 133-146

Author(s):

Oleksii Korzhyk ◽

Sergey Naida ◽

Sergii Kurdiuk ◽

Valeriia Nizhynska ◽

Maxim Korzhyk ◽

...

Keyword(s):

Boundary Conditions ◽

Sound Radiation ◽

Zero Order ◽

Operating Conditions ◽

Oscillatory Process ◽

Stationary Mode ◽

Acoustic Transducers ◽

Electroacoustic Transducer ◽

Pass Through ◽

Wave Problems

In the article was solved the problem of radiation of a sound by the electroacoustic transducer which is executed in the form of a thin spherical cover, using a pass-through method. The outer and inner surfaces of the shell are completely electroded. The application of this method provides an opportunity to avoid inaccuracies that arise during the traditional formulation of boundary conditions for acoustic mechanical fields, the use of equivalent substitution schemes and the absence of boundary conditions for the electric field in general. Given methodology eliminates these shortcomings by applying conjugation conditions, taking into account the types of electroding of the surfaces of piezoceramic transducers, the introduction of boundary conditions for current and voltage. The results of the solution demonstrate the high capabilities of this pass-through method, in terms of taking into account the peculiarities of determining the characteristics of these fields, values and dependences of the main complex characteristics of the electroelastic transducer, and auxiliary material constants of the piezoelectric material. The proposed approach is relevant, because it allows to increase the reliability of modeling the operating conditions of acoustic transducers in the context of wave problems of acoustics. Aim is to enhance the range of performances and build algorithms solving problems of stationary mode hydroelectroelasticity sound radiation. The expected results are presented in terms of improving approaches to studying the features of the oscillatory process of the active elements of sound-emitting systems and the accompanying effects of the transformation of interconnected fields involved in the formation of the acoustic signal in the liquid

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Improvements in Software DOMUS about Atmospheric Radiative Exchange and Long-wave Boundary Conditions

10.26678/abcm.encit2018.cit18-0231 ◽

2018 ◽

Author(s):

Santiago Riquelme ◽

Nathan Mendes ◽

Luís Mauro Moura

Keyword(s):

Boundary Conditions ◽

Long Wave ◽

Wave Boundary ◽

Radiative Exchange

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Open boundary conditions for horizontal 2-D curvilinear-grid long-wave dynamics of a strait

Advances in Water Resources ◽

10.1016/0309-1708(95)00017-d ◽

1995 ◽

Vol 18 (5) ◽

pp. 267-276 ◽

Cited By ~ 15

Author(s):

A.A. Androsov ◽

K.A. Klevanny ◽

E.S. Salusti ◽

N.E. Voltzinger

Keyword(s):

Boundary Conditions ◽

Open Boundary ◽

Open Boundary Conditions ◽

Wave Dynamics ◽

Long Wave ◽

Curvilinear Grid

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