• 대한기계학회논문집B
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• 제25권1호
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• pp.62-70
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• 2001

Three-dimensional dynamic stall over an oscillating wing has been analyzed by using a compressible Navier-Stokes code. The code solved the thin-layer Navirer-Stokes equations with a second-order time accuracy for a semispan wing with 0.3048m chord, a NACA 0015 airfoil section, and zero twist Computations were made for a freestream Mach number of 0.29, a chord Reynolds number of 1.95$\times$10(sup)6 and a reduced frequency equal to 0.1. Numerical results were compared with experimental data which include the hysteresis of lift, drag and moment at various wing span. The comparison reveals the quantitative as well as qualitative nature of the three-dimensional dynamic stall.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.205-212
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• 2006

Three-dimensional numerical study was carried out for the investigation of the detonation wave structures propagating in tubes. Fluid dynamics equations and conservation equation of reaction progress variable were analyzed by a MUSCL-type TVD scheme and four stage Runge-Kutta time integration. Chemical reaction was modeled by using a simplified one-step irreversible kinetics model. The variable gas properties between unburned and burned states were considered by using variable specific heat ratio formulation. The unsteady computational results in three-dimension show the detailed mechanisms of rectangular and diagonal mode of detonation wave instabilities resulting same cell length but different cell width in smoked-foil record. The results for the small reaction constant shows the spinning mode of three-dimensional detonation wave dynamics, which was rarely observed in the previous numerical simulation of the detonation waves.

• 한국전산유체공학회지
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• 제10권3호
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• pp.19-26
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• 2005

The purpose of this paper is the study on the characteristics of an inlet system with shock/boundary layer interactions by using various types of bumps which are substituted for the conventional bleeding system in supersonic inlet. in this study a comprehensive numerical analysis has been performed to understand the three-dimensional flow field including shock/boundary layer interaction and growth of turbulent boundary layer that might occur around a three-dimensional bump in a supersonic inlet. The characteristics of boundary layer seen in the current numerical simulations indicate the potential capability of a three-dimensional bump to control shock/boundary layer interaction in supersonic inlets.

• 한국유체기계학회 논문집
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• 제13권3호
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• pp.59-64
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• 2010

To analyze the three-dimensional flow in tunnel caused by operation of jet fan, both experimental and computational studies have been conducted. The experimental analysis of tunnel flow induced by jet fan is conducted on a real-scale apparatus with jet fan and tunnel, and air velocity at the monitoring points is measured for variation of fan's RPM. The three-dimensional numerical analysis including tunnel and jet fan is carried out for the same geometric configuration as the experimental analysis. The experimental and computational results are compared to examine the applicability of the numerical method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.828-830
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• 2000

This paper describes BIEM(Boundary Integral Equation Method) for computation of three dimensional electric field distribution and numerical method that an equivalent charge density is unknown variable. After computing numerically the surface charge distribution. the distribution of both potential and electric field are obtained. Finally, this numerical method is applied to the concentric sphere and the coaxial cylindrical model and numerical result is compared to the analytic solution.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1995년도 추계 학술대회논문집
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• pp.188-193
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• 1995

Incompressible developing entry flows through square ducts with 90 degree bends are studied numerically by using an efficient implicit SMAC scheme with different boundary conditions. This study eventually aimed at passage flow analysis of turbomachinery elements with a strong curvature such as centrifugal impeller or draft tube. The generalized implicit scheme used in the present study has been developted to solve the three-dimensional Navier-Stokes equations by the author. Numerical results for some different numerical conditions are obtained and compared with each other

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1750-1756
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• 2001

Three-dimensional and unsteady flow analysis is a practical target of high performance computation. As recently advances of computers, a numerical prediction by the large eddy simulation (LES) are introduced and evaluated for various engineering problems. Its advanced methods for the complex turbulent flows are discussed by several examples applied for aerodynamic designs, analysis of fluid flow mechanisms and their interaction to complex phenomena. These results of time-dependent and three-dimensional phenomena are visualized by interactive graphics and animations.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 추계 학술대회논문집
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• pp.182-187
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• 2003

Numerical analysis of three-dimensional vicous flow is used to compute the design speed operating line of a transonic axial-flow compressor. The Navier-Stokes equation was solved by an explicit finite-difference numerical scheme and the Baldwin-Lomax turbulence model was applied. A spatially-varying time-step and an implicit residual smoothing were used to improve convergence. Two-stage axial compressor of a turboshaft engine developed KARI was chosen for the analysis. Numerical results show reasonably good agreements with experimental measurements made by KARI. Numerical solutions indicate that there exist a strong shock-boundary layer interaction and a subsequent large flow separation. It is also observed that the shock is moved ahead of the blade passage at near-stall condition.

• Journal of Mechanical Science and Technology
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• 제19권7호
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• pp.1488-1502
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• 2005

A three dimensional model was developed to analyze the mold filling and solidification in the casting processes. The model uses the VOF method for the calculation of the free surface and the modified Equivalent Specific Heat method for the treatment of the latent heat evolution. The solution procedure is based on the SIMPLER algorithm. The complete model has been validated using the exact solutions for phase change heat transfer and the experimental results of broken water column. The three-dimensional model has been applied to the benchmark test and the results were compared to those from experiment, a two-dimensional analysis, and another three dimensional numerical model.

• 콘크리트학회지
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• 제8권2호
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• pp.119-127
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• 1996

본 연구는 철근콘크리트 부재의 3차원 재료적 비선형해석을 하기 위한 것이다. 콘크리트는 3축 비선형 응력-변형률 거동, 균열, 파쇄 및 변형률완화를 포함하는 3차원 16절점 고체요소를 사용하고, 철근은 변형률경화를 갖는 3차원 3절점 트러스요소를 사용한다. 균열 후 골재의 맞물림을 고려하는 유효전단계수를 평가하기 위해서 균열의 진행여부에 따른 전단유지계수를 도입하였으며, 수치해를 얻기 위해 수정뉴턴방법을 사용하였다. 가우스점에서의 해석결과는 그래픽으로 확인된다. 수치예제로서 Krahl의 철근콘크리트 보와 Hedgren의 철근콘크리트 쉘을 채택하여 해석결과와 비교하였다.