• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 1998년도 춘계 학술대회논문집
• /
• pp.123-127
• /
• 1998

A computer code has been developed for an analysis of conduction and convection heat transfer on a personal computer. FVM based on unstructured mesh has been employed for triangular and quadrilateral element. All variable of p, u, v, T, k and ${\varepsilon}$ has been defined on a node (not on a center of element). The code possesses the pre-and post-processor for itself to provide user-friendly interface.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 1997년도 추계 학술대회논문집
• /
• pp.55-60
• /
• 1997

An unstructured finite volume method is presented for seeking steady and unsteady flow solutions of the two-dimensional incompressible viscous flows. In the present method, SMAC-type algorithm is implemented on unstructured triangular meshes, using second order upwind scheme for the convective fluxes. Validation tests are made for various steady and unsteady incompressible flows. Convergence characteristics are examined and accuracy comparisons are made with some benchmark solutions.

• 소성∙가공
• /
• 제13권3호
• /
• pp.205-210
• /
• 2004

The waveguide Bragg gratings have been fabricated by the phase-mask method. An excimer laser with maximum 600mJ output pulse energy and uniform phase masks have been used. Hydrogen loading is often used for enhancing the uv photosensitivity of the core, however, the resultant gratings show significant aging effect. In the present study, high temperature thermal annealing process has been investigated to obtain thermal gratings and process parameters are deduced.

• 한국농림기상학회:학술대회논문집
• /
• 한국농림기상학회 2019년도 하계 학술발표초록집
• /
• pp.206-207
• /
• 2019

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2009년 춘계학술대회논문집
• /
• pp.31-38
• /
• 2009

In the present study, viscous flow calculations of helicopter main rotor system in forward flight were made by using an unstructured hybrid mesh solver. Each rotating blade relative to the cartesian frame was simulated independently by adopting unstructured overset mesh technique. For the validation of the present method, calculations for the Caradonna-Tung non-lifting forward flight and the AH-1G main rotor system in forward flight were made. Additional computation was made for the UH-60A rotor in forward flight. Reasonable agreements were obtained between the present results and the experiment.

• 한국전산유체공학회지
• /
• 제16권4호
• /
• pp.72-83
• /
• 2011

A high-order discontinuous Galerkin method for the two-dimensional compressible Navier-Stokes equations was developed on unstructured triangular meshes. For this purpose, the BR2 methd(the second Bassi and Rebay discretization) was adopted for space discretization and an implicit Euler backward method was used for time integration. Numerical tests were conducted to estimate the convergence order of the numerical solutions of the Poiseuille flow for which analytic solutions are available for comparison. Also, the flows around a flat plate, a 2-D circular cylinder, and an NACA0012 airfoil were numerically simulated. The numerical results showed that the present implicit discontinuous Galerkin method is an efficient method to obtain very accurate numerical solutions of the compressible Navier-Stokes equations on unstructured meshes.

• 한국분무공학회지
• /
• 제8권1호
• /
• pp.1-8
• /
• 2003

The flow analysis of the axial fan of rotary burner was performed by SIMPLE(Semi Implicit Method for Pressure Linked Equations) algorithm and finite volume mothod performed in the case of 3-D, incompressible, turbulent flow. In this study, the coordinate transformation was adapted for the complex geometry of axial fan, and the standard $k-{\varepsilon}$ model and wall function method were used for analysis of turbulent flow. Multi-block grid system was used for flow field and divided into four domains such as the inlet, outlet, flow field of rotating vane, and tip clearance. Fan rotation was simulated by rotational motion using MRF(Multiple Rotating Reference Frame) in steady, incompressible state flow.

• 전자공학회논문지B
• /
• 제30B권5호
• /
• pp.34-42
• /
• 1993

Due to the low loss, broadband and accurate short time delay properties of optical fiber, it has attracted as a delay medium for high speed and broad-band signal processing. In this paper, we consider the coherent optical fiber filter of lattice structure, which uses coherent light sources and consists of directional couplers and optical fiber delay elements.The differences between the optical fiber filter and the ordinary digital filter are 1) the coupling coefficients of directional couplers are restricted between 0 and 1. 2) the optical signal is divided into ${j\sqrt{a}}and\;{j\sqrt{1-a}}$ at the directional coupler. Considering these restrictions, the design formulae and condition of realibility for optical fiber filter of lattice structure which makes the optimal use of optical signal energy are derived.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2011년 춘계학술대회논문집
• /
• pp.20-24
• /
• 2011

In this paper, numerical simulation of cavitation flow for modified NACA66 hydrofoil was made by using the multi-phase RANS equation based on pseudo-compressibility. The Homogeneous mixture model comprised of the mixture continuity, mixture momentum and liquid volume fraction equations was utilized. A vertex-centered finite-volume method was used in conjunction 2nd-order Roe's FDS to discretize the inviscid fluxes. The viscous fluxes were computed based on central differencing The Spalart-Allmaras one equation model was employed for the closure of turbulence. Reasonable agreements were obtained between the calculation results and the experiment for pressure coefficients on the hydrofoil surface.

• 대한조선학회논문집
• /
• 제34권3호
• /
• pp.113-118
• /
• 1997

본 연구에서는 해상누유의 시간변화에 따른 오염지역 예측을 위한 수학모델 및 수치기법을 제안하였다. 본 모델은 기름의 분자적인 확산 뿐만아니라 해수의 표층유동에 기인한 기름의 이동을 동시에 고려하는데 그 특징이 있다. 그리고, 실제 누유사고에의 보다 실용적이고 효율적인 응용을 위해 자동적으로 계산대상영역을 설정하는 격자수정방법을 도입하였다. 본 계산기법을 다양한 가상의 누유사고에 대해 적용해 본 결과, 매우 사실적인 누유오염지도를 얻을 수 있을 것으로 여겨진다.