• Journal of the Society of Naval Architects of Korea
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• v.43 no.6 s.150
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• pp.647-655
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• 2006

In this paper, submerged body dynamics model in vertical plane which can include the effect of free surface and wave is suggested to simulate the motions of submerged body moving beneath free surface precisely. A controller is designed, which can maintain a constant depth below the mean sea level and minimize the pitch angle. Numerical simulations show that the designed controller is effective on depth keeping and minimizing pitch angle in regular waves and irregular waves.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.399-406
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• 1998

Transient acoustic and elastic wave propagation in inhomogeneous media are studied by using the Fourier method. To verify the proposed numerical scheme, several examples having analytic solutions are considered, where two different semi-infinite media are in contact along a plane boundary. The comparisons of numerical results by the Fourier method and analytic solutions show good agreements. In addition, the Fourier method is applied to a layered half-plane, in which an elastic semi-infinite medium is covered by an elastic layer of finite thickness. It is showed how to derive the analytic solutions by using the Cagniard-de Hoop method. The numerical solutions are in excellent agreements with analytic results.

• Earthquakes and Structures
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• v.9 no.3
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• pp.577-601
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• 2015

The thermomagnetic effect on plane wave propagation at the liquid-solid interface with nonclassical thermoelasticity is investigated. It is assumed that liquid-solid half-space is under initial stress. Numerical computations are performed for the developed amplitude ratios of P, SV and thermal waves under Cattaneo-Lord-Shulman theory, Green-Lindsay theory and classical thermoelasticity. The system of developed equations is solved by the application of the MATLAB software at different angles of incidence for Green and Lindsay model. The effect of initial stress and magnetic field in the lower half-space are discussed and comparison is made in LS, GL and CT models of thermoelasticity. In the absence of magnetic field, the obtained results are in agreement with the same results obtained by the relevant authors. This study would be useful for magneto-thermoelastic acoustic device field.

• Steel and Composite Structures
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• v.27 no.4
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• pp.439-451
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• 2018

In the present investigation, a plane P (longitudinal) wave is made incident upon a transversely isotropic magnetothermoelastic solid slab of uniform thickness, interposed between two different semi-infinite viscoelastic solids. The transversely isotropic magnetothermoelastic sandwiched layer is homogeneous with combined effects of two temperature, rotation and Hall current in the context of GN Type-II and Type-III (1993) theory of thermoelasticity. The amplitude ratios of various reflected and refracted waves are obtained by using appropriate boundary conditions. The effect of energy dissipation on various amplitude ratios of longitudinal wave with angle of incidence are depicted graphically. Some cases of interest are also deduced from the present investigation.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.12
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• pp.21-29
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• 1998

Dual integral equation in the spectral domain is derived for an arbitrary angled perfect conducting wedge with E-polarized plane wave incidence. Analytic integration of the dual integral equation in the spectral domain with the exact boundary fields of the perfect conducting wedge, the well known series solution, gives the exact asymptotic solution. The validity of the integration is assured by showing that analytic integration gives the null fields in the complementary region.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.143-150
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• 1999

Elastic wave propagation in a multilayered elastic half-plane is studied by using the Cagniard-de Hoop method. After the unknowns are expressed in terms of the reflection and transmission coefficients in the in terms of the reflection and transmission coefficients in the integral-transformed domains they are assmbled to form the global matrix equation. The inverse Laplace transform of each term is done by applying the Cagniard-de Hoop methods. As a numerical example a four-layered half-plane is considered where a point source is applied to the first layer. The method described in the present study can be used in checking other numerical methods such as FDM.

• Korean Journal of Optics and Photonics
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• v.2 no.2
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• pp.74-82
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• 1991

This study is to investigate the distribution of the radiation force exerted on a homogeneous sphere by two circularly-polarized counterpropagating $TEM_{00}$ laser beams. The time-averaged expressions of the rediation force are derived for both cases of two interfering $TEM_{00}$ laser beams and a standing plane electromagnetic wave. The radiation force is numerically calculated and the physical interpretations of computed results are presented. The results in this paper will be useful in the optical levitation experiment using two counterpropagating $TEM_{00}$ laser beams or a standing plane electomagnetic wave.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.3
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• pp.232-242
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• 1990

This paper presents the formulas for load currents of a cascaded transmission line excited by external plane wave using Smith's method for EMI currents of a single transmission line. Calculating under the condition that the lines having same characteristic impedence are cascaded, numerical results of this study are well agreed with those of Smith and show the fact that as the width and length of the line reduced to 1/10 respectively, the load-EMI currents decreased by about 40dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.605-610
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• 1997

An analysis method for the electromagnetic scattering of a Tm polarized plane wave from a periodic strip grating over a grounded dielectric slab is considered from the viewpoint of reflection grating problem. The parameters of strip gratings showing Bargg and Off-Bragg blazing phenomena at the frequency of 10GHz are derived teoretically. The strip grating structure is implemented using Aluminum plate(groung conductor), paraffin(dielectric material.epsilon.$_{r}$=2.24), and copper(strip conductor0.08m thickness). The experimental results(reflection power) of Bragg as well as Off-Bragg blazing phenomenon for TM polarized plane wave have been compared with the theoretical results and fairly good agreements between theory and experiment have been observed.d.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.314-318
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• 2008

We investigate the conditions of the complete tunneling of light across a composite barrier made of multiple layers involving metamaterials. It is shown that complete tunneling phenomena are related to the resonance transmission properties of local modes formed in barrier layers and that there are two distinctive kinds of local barrier modes involved in actual complete tunneling: the degenerate inner-barrier mode and the full barrier mode. Complete tunneling occurs via two successive mode couplings: from the incident plane wave to the plane wave in the transmission layer through the direct mediation of these two kinds of local barrier modes.