• 대한조선학회지
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• 제24권3호
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• pp.9-16
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• 1987

In this paper, the fluid flow in the two-dimensional tank is analyzed by the Finite Difference Method. The Navier-Stokes equation is modified for the tank fixed coordinate system. For the treatment of the free surface, the Volume of Fluid Method by Hirt and Nichols is adopted. The continuity equation and the Poisson equation which is derived from the Navier-Stokes equation to find the pressure are solved by the Successive-Line-Overrelaxation Method. The comparison of the calculated results with experimental data show a favorable agreement. The fluid flow in the two-dimensional tank can be predicted reasonably before the free surface reaches breaking by this numerical method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.7-8
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• 2009

본 연구에서는 콘크리트 피복두께가 철근콘크리트 기둥의 횡방향 심부구속철근량 산정식에 미치는 영향을 비교, 분석하고 보다 합리적인 철근콘크리트 교각의 내진설계를 위한 횡방향 심부구속철근량 산정식을 수정 제안하였으며 국내 외에서 수행된 실험결과를 바탕으로 제안식의 안전율 및 타당성을 검증하였다.

• 한국세라믹학회지
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• 제31권12호
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• pp.1545-1551
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• 1994

Various kinetic parameters of the nucleation and crystallization in anorthite glass (CaO.Al2O3.2SiO2) were calculated by nonisothermal differential thermal analysis. Base glass and glass with TiO2 were prepared by melting. In base glass, the temperature where nucleation can occur ranges from 85$0^{\circ}C$ to 9$25^{\circ}C$ and the temperature for maximum nucleation was 900$\pm$5$^{\circ}C$. In glass with TiO2, the nucleation temperature range was 800~875$^{\circ}C$ and the maximum nucleation temperature was 850$\pm$5$^{\circ}C$. Kissinger equation, Bansal equation, and modified Ozawa equation were used for calculating activation energy for crystallization, Ec. The results showed the same activation energies for both glasses with and without TiO2 in the different equations. The shape of maximum exotherm peak and Ozawa equation were used for Avrami exponent, n. The n value for each glass was 2, indicating that each glass crystallized primarily by bulk crystallization.

• 대한전기학회논문지
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• 제36권3호
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• pp.153-162
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• 1987

The purpose of this paper is to analysis and develop theoretically the characteristics of tubular linear induction motor, which is a special industrial motor that generates directly thrust force from electrical power. The Poisson equation about vector potential which is created by the application of Maxwell electromagnetic equation with the speed considered, results in modified Bessel equation by the assumption that is applied to each region of the experimental motor. Vector potential, magnetic flux density, secondary current, and thrust force according to its region respectively were found out by substituting boundary condition for this equation and rearranging. Besides, a attendant materials, that is, thermal characteristic, which is one of the characteristics under the operation of experimental motor each part's magnetic flux distribution characteristics within active zone, the required time for reciprocating motion, and variation of power factor vs. a slip were found.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.461-466
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• 1989

This paper describes some properties of a discrete algebraic Riccati equation and its application to $H^{\infty}$ control design. The conditions, under which an input weighting matrix can be found for a negative output weighting matrix in order that a solution P for a discrete algebraic equation may exist, are suggested in case of a stable A. This result is applied to a $H^{\infty}$ controller design for the special case of nonsingular B. It is based on a state feedback control law whose objective is to reduce the effect of input disterbances below a prespecified level. This law requires the solution of a modified algebraic Riccati equation, which provides an method for the $H^{\infty}$ optimization control problem approximately.ly.

• 대한기계학회논문집
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• 제18권6호
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• pp.1355-1364
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• 1994

This paper analyzes the running mechanism of flexible and thin foil above rotating protrusion through a numerical simulation. The scope of analysis is confined to the phenomena of elastohy-drodynamic lubrication between the stationary and rotary drums with a running protrusion and thin foil. This mathematical model is based on the modified Reynolds equation and the equation of plate, considering the geometry of protrusion, running direction of protrusion, and the effect of geometric nonlinearity. Finite element method is adopted as a numerical simulation technique to solve the avobe coupled nonlinear equations. In numerical analysis, the effects of the scanning angle in Reynolds equation and the nonlinear term in plate equation are evaluated. Furthermore, the simulation is applied to the situation that thin foil is located in the entire drums (stationary and rotary drums).

• 대한기계학회논문집
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• 제5권4호
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• pp.257-265
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• 1981

A modified subsonic wind tunnel was employed to investigate the turbulent flow of a valve jet. To effectuate this experimental study, an actual valve and valve seat of a diesel engine were equipped at its outlet (ref. Fig. 3) Theoretically, using the equation of motion of Navier-Stokes in the chlindrical coordinates, the turbulent equation of motion for the incompressible fluid was derived with three assumptions; steady flow (.delta./.delta.t=0), axisymmetry and revolutionary homogeneity(.delta./.delta..phi.=0), no ensemble revolution (V.iden.0). Experimentally, mean and fluctuation velocities have been measured in the redial direction. With a assumption of a non-dimensional velocity distribution equation, a sami-emperical similarity profile equation of the jet flow have been derived, whose empirical constants were deterimed graphically with the data obtained.

• 항공우주시스템공학회지
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• 제10권1호
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• pp.8-14
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• 2016

The optimal estimation of a bearing only target tracking problem be achieved through the solution of the Fokker-Planck equation and the Bayesian update. Recently, a nonlinear filtering algorithm using a direct quadrature method of moments in which the associated Fokker-Planck equation can be propagated efficiently and accurately was proposed. Although this approach has demonstrated its promising in the field of nonlinear filtering in several examples, the "degeneracy" phenomenon, similar to that which exists in a typical particle filter, occasionally appears because only the weights are updated in the modified Bayesian rule in this algorithm. Therefore, in this paper to enhance the performance, a more stable measurement update process based upon the update equation in the Extended Kalman filters and a more accurate initialization and re-sampling strategy for weight and abscissas are proposed. Simulations are used to show the effectiveness of the proposed filter and the obtained results are promising.

• 한국세라믹학회지
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• 제30권1호
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• pp.78-84
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• 1993

In PMN-pyrochlore phase mixtures, dielectric constant was measured as a function of the volume fraction of pyrochlore phase and considered with general effective media(GEM) equation. For the application of GEM equation to this system, the critical volume fraction(Vc) where connectivity between the perovskite PMN and pyrochlore phase changed from 0-3 to 3-3, was determined based on the each particle size ratio of two phases with microstructural observation. And then the t value was determined from modified percolation powder-law dependence ( K-Kc (V-Vc)t). In the case of applying such values of t and Vc to the GEM equation, which provided a reasonable fit to the measured dielectric constant within the experimental error range.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1998년도 춘계 학술대회논문집
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• pp.138-144
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• 1998

The BGK equation, which is the kinetic model equation of Boltzmann equation, is solved using FDDO(finite difference with the discrete-ordinate method) to compute the rarefied flow of monatomic gas. Using reduced velocity distribution and discrete ordinate method, the scalar equation is transformed into a system of hyperbolic equations. High resolution ENO(Essentially Non-Oscillatory) scheme based on Harten-Yee's MFA(Modified Flux Approach) method with Strang-type explicit time integration is applied to solve the system equations. The calculated results are well compared with the experimental density field of NACA0012 airfoil, validating the developed computer code. Next. the computed results of circular cylinder flow for various Knudsen numbers are compared with the DSMC(Direct Simulation Monte Carlo) results by Vogenitz et al. The present scheme is found to be useful and efficient far the analysis of two-dimensional rarefied gas flows, especially in the transitional flow regime, when compared with the DSMC method.