• Bulletin of the Korean Mathematical Society
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• v.48 no.4
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• pp.873-896
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• 2011

The semi-discrete central scheme and central upwind scheme use Runge-Kutta (RK) time discretization. We do the Lax-Wendroff (LW) type time discretization for both schemes. We perform numerical experiments for various problems including two dimensional Riemann problems for Burgers' equation and Euler equations. The results show that the LW time discretization is more efficient in CPU time than the RK time discretization while maintaining the same order of accuracy.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.8-13
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• 1993

This paper presents deterministic and adaptive control laws for two-link flexible arm. The flexible arm has considerable structural flexibility. Because of its flexbility, dynamic equations are very complex and difficult to get, dynamic equations for two-link flexible arm are derived from Bernoulli-Euler beam theory and Lagrangian equation. Using the fact that matrix is skew symmetric, controllers which have a simplified structure with less computational burden are proposed by using Lyapunov stability theory.

• 한국전산유체공학회:학술대회논문집
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• 1998.11a
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• pp.191-196
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• 1998

A two-dimensional airfoil flying over a wavy wall is calculated by solving the unsteady Euler equation. Unsteady Transonic flow over an NACA00012 airfoil in pitching motion has been computed for code validation. Some numerical results for NACA6409 airfoil under different wave number, wave length, fly height are presented. The numerical results show the variation of lift and pitching moment coefficients are increased as wave length decrease.

• Journal of the Korean Mathematical Society
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• v.34 no.3
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• pp.515-531
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• 1997

In this paper, finite difference method is applied to approximate the generalized solutions of Sobolev equations. Using the Steklov mollifier and Bramble-Hilbert Lemma, a priori error estimates in discrete $L^2$ as well as in discrete $H^1$ norms are derived frist for the semidiscrete methods. For the fully discrete schemes, both backward Euler and Crank-Nicolson methods are discussed and related error analyses are also presented.

• Communications of the Korean Mathematical Society
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• v.22 no.4
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• pp.609-621
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• 2007

Comparison of high Mach number jets using positive schemes and Weighted ENO methods is considered in this paper. The positive scheme introduced by [11, 14] and Weighted ENO [9, 10] have allowed us to simulate very high Mach numbers more than Mach 80. Simulations at high Mach numbers and with radiative cooling are essential for achieving detailed agreement with astrophysical images.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.679-680
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• 2011

The Forced vibration characteristics of elastically restrained pipe conveying fluid with the attached mass are investigated in this paper. Based on the Euler-Bernoulli beam theory, the equation of motion is derived by using Hamilton's principle. The effect of attached mass and spring constant on forced vibration of pipe system is studied. Also, the critical flow velocities and stability maps of the valve-pipe system are obtained as each parameters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.435-440
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• 2002

The free vibration of partially embedded piles is investigated. The pile model is based on the Bernoulli-Euler beam theory and the soil is idealized as a Winkler model for mathematical simplicity. The governing differential equation for the free vibrations of such members is solved numerically The piles with one typical end constraint (clamped/hinged/free) and the other hinged end with rotational spring are applied in numerical examples. The lowest three natural frequencies are calculated over a range of non-dimensional system parameters: the rotational spring parameter, the relative stiffness and the embedded ratio.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.206-211
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• 1999

The purpose of this study is to investigate the natural frequencies and mode shapes of beam-columns on the non-homogeneous foundaion. The beam model is based on the classical Bernoulli-Euler beam theory. The linear foundation modulus is chosen as the non-homogeneous foundation in this study . The differentidal equation goeverning free vibrations of such beam-columns subjected to axial load is derived and solved numerically for calculting the natural frquencies and mode shapes. In numerical fivekinds of end constraint are considered, and the lowest four natural frquencies and corresponding mode shape are obtained as the non-dimensional forms.

• Bulletin of the Society of Naval Architects of Korea
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• v.25 no.2
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• pp.1-10
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• 1988

An axially marching numerical method is developed for the simulation of the internal waves produced by translation of a submersed vehicle in a density-stratified ocean. The method provides for the direct solution of the primitive variables [$\upsilon,\;p,\;\rho$] for the nonlinear and steady state three-dimensional Euler's equation with a non-constant density term in the vehicle-fixed cartesian co-ordinate system. By utilizing a known potential flow around the vehicle for an estimate of the axial velocity gradient, the present parabolic algorithm local upstreamwise disturbances and axial velocity variation.

• Structural Engineering and Mechanics
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• v.29 no.5
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• pp.551-565
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• 2008

Transient solution of asymmetric mechanical and thermal stresses for hollow cylinders made of functionally graded material is presented. Temperature distribution, as function of radial and circumferential directions and time, is analytically obtained, using the method of separation of variables and generalized Bessel function. A direct method is used to solve the Navier equations, using the Euler equation and complex Fourier series.