• Wind and Structures
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• v.19 no.1
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• pp.35-58
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• 2014

A numerical simultaneous solution involving a linear elastic model was applied to study the fluid-structure interaction (FSI) of membrane structures under wind actions, i.e., formulating the fluid-structure system with a single equation system and solving it simultaneously. The linear elastic model was applied to managing the data transfer at the fluid and structure interface. The monolithic equation of the FSI system was formulated by means of variational forms of equations for the fluid, structure and linear elastic model, and was solved by the Newton-Raphson method. Computation procedures of the proposed simultaneous solution are presented. It was applied to computation of flow around an elastic cylinder and a typical FSI problem to verify the validity and accuracy of the method. Then fluid-structure interaction analyses of a saddle membrane structure under wind actions for three typical cases were performed with the method. Wind pressure, wind-induced responses, displacement power spectra, aerodynamic damping and added mass of the membrane structure were computed and analyzed.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.4
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• pp.593-602
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• 2004

This paper is a study on the model of simultaneous heat and mass transfer process in the absorption of refrigerant vapor into a lithium bromide solution of water-cooled vertical plate absorber. The model can predict temperature and concentration profiles as well as the effect of Reynolds number on them. Also. the variations of the absorption heat and mass fluxes. and the heat and mass transfer coefficients have been investigated. The numerical result shows that the interface temperature and concentration decrease as film Reynolds number does. The absorption heat and mass fluxes, and the heat and mass transfer coefficients get their maximum values adjacent to the inlet solution. Analyses on a constant wall temperature condition have been also carried out to exam the reliability of the present numerical method by comparing to previous investigations.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.41-47
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• 2002

A model of simultaneous heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water-cooled vertical plate absorber was developed. The model can predict temperature and concentration profiles as well as the absorption heat and mass fluxes, the total heat and mass transfer rates and the heat and mass transfer coefficients. Besides, the effect of operating condition on absorption mass flux has been investigated, with the result that the absorption mass flux is increased as the inlet cooling water temperature decreases, the system pressure increases and the inlet solution concentration increases. And among the effects of operating parameters on absorption mass flux, the effect of inlet solution concentration is dominant.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.77-83
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• 2007

This paper presents numerical and experimental works for simultaneous pumping and mixing small liquid using asymmetric microelectrode arrays, based on AC electroosmotic flows. To this end, four arrangements of electrode pairs were considered with diagonal/herringbone shapes. Numerical simulations were made of three-dimensional geometries by using the linear theory. The results indicated that the helical flow motions induced by the electrode arrays play a significant role in the mixing enhancement. The pumping performance was influenced by the slip velocity at the center region of the channel compared to that near the side walls. To validate the numerical predictions, the microfluidic devices were made through MEMS. The flow rate was obtained by using micro PIV, increasing the applied frequency. The electrolyte was potassium chloride solution. The flow patterns above electrodes were visualized to see lateral flow for mixing. The experimental results showed good agreements with the numerical predictions.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.956-961
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• 2004

This paper proposes a study on the spherical lens manufacturing by simultaneous 3 axis for NC lathe. We use friction drive system for moving system in experimental diamond turing machine. The diamond turning machine use manufacturing for high quality lens, mirror and many optics products. Especially, the high tech industry require a lot of lens. For example, optical engineering. medical science, space engineering and material engineering etc. The friction drive system is very simple and quiet, compared to ball screw system. We find a problem at the simultaneous 3 axis and suggest a solution. Also, when we manufactured a micro lens. find a problem and solution.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.5
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• pp.440-446
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• 1996

The multiple-ridged circular waveguides is analyzed using Fourier series and the mode matching technique. The enforcement of the boundary conditions yields the simultaneous equations for the field coefficient inside the waveguides. The simultaneous equations are solved to represent a dispersion relation in an analytic series form. The numerical computation is performed to illustrate the behavior of the cutoff wavenumbers in terms of number, length and angle of ridges. The presented series solution is exact and rapidly-convergent so that it is efficient for numerical computation. A simple dispersion relation based on the dominant mode analysis is obtained and is shown to be very accurate for most practical applications.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.9 no.2
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• pp.17-27
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• 2005

The problem of the onset stability in an inclined layer of dielectric viscoelastic fluid (Walter's liquid B') is studied. The analysis is made under the simultaneous action of a normal a.c. electric field and the natural convection flow due to uniformly distributed internal heat sources. The power series method used to obtain the eigen value equation which is then solved numerically to obtain the stable and unstable solutions. Numerical results are given and illustrated graphically.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.13-19
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• 2007

An numerical method to estimate thermal diffusivity has been developed for one-dimensional unsteady heat conduction problem, when the temperatures are know at two positions in a semi-infinite body. Using the closed form solution which has already derived an explicit solution for the inverse problem for one-dimensional transient heat conduction using Laplace transform technique, we first estimate the surface temperature. The thermal diffusivity can be estimated by using the estimated surface temperature and measured temperatures, which include some uncertainties. The estimated surface heat flux and thermal diffusivity are found to be in good agreement with those of the experimented conditions. This method will be extended to the simultaneous measurement of thermal diffusivity and thermal conductivity.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.4
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• pp.33-37
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• 1991

The problem of radiation from a flanged parallel-plate waveguide is re-examined. The technique of the Fourier transform is used to represent the radiation fields in the spectral domain. The simultaneous equations for the radiation field coefficients are formulated and solved to give an asymptotic seolution. The asymptotic series solution is compared with other results, thus clarifying the discrepancy among different numerical approaches.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1353-1362
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• 2003

This paper considers a simultaneous optimization problem of structure and control systems. The problem is generally formulated as a non-convex optimization problem for the design parameters of mechanical structure and controller. Therefore, it is not easy to obtain the global solutions for practical problems. In this paper, we parameterize all design parameters of the mechanical structure such that the parameters work in the control system as decentralized static output feedback gains. Using this parameterization, we have formulated a simultaneous optimization problem in which the design specification is defined by the Η$_2$and Η$\_$$\infty$/ norms of the closed loop transfer function. So as to lead to a convex problem we approximate the nonlinear terms of design parameters to the linear terms. Then, we propose a convex optimization method that is based on linear matrix inequality (LMI). Using this method, we can surely obtain suboptimal solution for the design specification. A numerical example is given to illustrate the effectiveness of the proposed method.