• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.512-517
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• 2001

In this study, spin-up flows in a rectangular container are analysed by using three-dimensional computation. In the numerical computation, we use the parallel computer system of PC-cluster type. We compared our results with those obtained by two-dimensional computation. Effect of velocity and vorticity on the flow is studied. The result shows that two-dimensional solution is in good agreement with the 3-D result. Attention is given to the region where the 3-D flow is significant.

• Radiation Oncology Journal
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• 제3권1호
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• pp.59-64
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• 1985

Computation of three dimensional dose distribution using CT image and RT plan was applied to a case of pituitary adenoma. Algorithm was based on two dimensional Tissue Maximun Ratio model extended to the third dimension. The resulting isodose curve of transeverse, coronal and sagittal section was demonstrated. This RT plan allows computation of dose distribution in any arbitarily defined plane in addition to conventional cross sectional view.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1995년도 추계 학술대회논문집
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• pp.182-187
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• 1995

The present paper explains some advancement made by the authors for the compressible flow computation of the Euler equations based on the unstructured grid and vertex- centered finite volume method. Accurate solutions to the unsteady axisymmetric shock wave propagation problems and three-dimensional airplane flows have been obtained by a high-order upwind TVD and FCT schemes. Unstructured grid adaption is made for the unsteady shock wave problems by the dynamic h-refinement/unrefinement procedure and for the three-dimensional steady flows by the Delaunay point-insertion method to generate three-dimensional tetrahedral mesh enrichment. Some physics of the shock wave diffraction phenomena and three-dimensional airplane flow are discussed.

• 대한기계학회논문집B
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• 제21권12호
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• pp.1595-1607
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• 1997

The natural convection of a horizontal layer heated from below in a three-dimensional rectangular enclosure was dealt with both numerically and experimentally. The aspect ratios are 1:2:3.5 and Boussinesq fluid is water with the Prandtl number of 5.0. This experimental study showed how to measure the variation of temperature field in a 3-D rectangular enclosure with small aspect ratios by using TLC(Thermochromic Liquid Crystal) and color capturing technique. The experimental temperature field had periodic characteristics of 75 sec at Ra=2.37*10$^{5}$ . But the numerical convection flow had periodic characteristics of 79 sec at the same Rayleigh number. In three dimensional computation it was found that the convection roll structure bifurcated from four rolls to two rolls as the Rayleigh number is increased.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.207-212
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• 2001

In this study, spin-up flows in a shallow rectangular container are analysed by using three-dimensional computation. We compared our results with those obtained by quasi three-dimensional computation. Our results show that quasi S-D solustion is not accurate enough and it provides far less damped solution.

• Journal of electromagnetic engineering and science
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• 제1권1호
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• pp.78-82
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• 2001

For fast capacitance computation, a simple mesh refinement technique on MLFMA(Multi-Level Fast Multipole Algorithm) is proposed The triangular meshes are refined mainly in the area which has heavy charge density. The technique is applied to the capacitance extraction of three dimensional conductors. The results show good convergence with comparable accuracy. An adaptive technique concerned with MLFMA is useful to reduce computation time and the number of elements without additional computational efforts in large three dimensional problems.

• 대한기계학회논문집B
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• 제27권5호
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• pp.628-634
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• 2003

We present numerical and experimental results of periodic flows inside a rectangular container under a background rotation. The periodic flows are generated by changing the speed of rotation periodically so that a time-periodic body forces produce the unsteady flows. In numerical computation, a parallel-computation technique with MPI is implemented. Flow visualization and PIV measurement are also performed to obtain velocity fields at the free surface. Through a series of numerical and experimental works, we aim to clarify, if any, the fundamental reasons \ulcornerf discrepancy between the two-dimensional computation and the experimental measurement, which was detected in the previous study for the same flow model. Specifically, we check if the various assumptions prerequisite for the validity of the classical Ekman pumping law are satisfied for periodic flows under a background rotation.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1988년도 가을 학술발표회 논문집
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• pp.13-17
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• 1988

An efficient model for three-dimensional analysis of multistory structures with flexible floor diaphragms is proposed in this paper. Three-dimensional analysis of a building structure using a finite element model requires tedious input data preparation, longer computation time, and larger computer memory. The model proposed in this study is developed by assembling a series of two-dimensional resisting systems and is considered to overcome the shortcomings of a three-dimensional finite element model without deteriorating the accuracy of analysis results. Static and dynamic analysis results obtained using the proposed model are in excellent agreements to those obtained using three-dimensional finite element models in terms of displacements, periods, mode shapes.

• 전산구조공학
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• 제2권1호
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• pp.47-53
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• 1989

An efficient model for three-dimensional analysis of multistory structures with flexible floor diaphrgms is proposed in this paper. Three-dimensional analysis of a building structure using a finite element model requires tedious input data preparation, longer computation time, and larger computer memory. The model proposed in this study is developed by assembling a series of two-dimensional resisting systems and is considered to overcome the shortcomings of a three-dimensional finite element model without deteriorating the accuracy of analysis results. Static and dynamic analysis results obtained using the proposed model are in excellent agreement with those obtained using three-dimensional finite element models in terms of displacement, periods, and mode shapes. Effects of floor diaphragm flexibility on seismic response of multistory building structures are investigated.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제20회 춘계학술대회 논문집
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• pp.41-44
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• 2003

현재까지 초음속 제트에 관한 많은 연구들이 수행되어져 왔지만, 초음속 제트의 3차원 구조에 관해서는 상세히 알려져 있지 않다. 본 연구에서는 수치해석을 통하여 초음속 제트의 3차원 구조를 상세히 연구한다. 수치계산에서는 TVD법을 비정상, 3차원, 압축성 오일러 방정식에 적용하였으며, 얻어진 수치해석 결과를 이용하여, 초음속 제트의 유동장을 가시화 하였다. 본 수치해석 결과로부터 초음속 제트의 3차원 구조는 2차원적 구조와 매우 다르며, 압력비에 크게 의존한다는 것을 알았다.