• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.150-151
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• 2003

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1996년도 춘계 학술대회논문집
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• pp.131-136
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• 1996

The numerical method for the flow field of a gas atomization process is presented. For the analysis of the compressible supersonic jet flow of a gas. an axisymmetric Navier-Stokes equations are solved using a LU-factored upwind method. The MUSCL type TVD scheme is used for the discretization of inviscid flux, whereas Steger-Warming splitting and LU factorization is applied to the implicit operator. For the validation of the present method, we computed the flow field around the simple gas atomizer proposed by Issac. The numerical results has shown excellent agreement with the experimental data.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 추계 학술대회논문집
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• pp.194-199
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• 2003

The studying is to analyze characteristic of air flow and is used to design in an automotive HVAC module. The RNG k-e turbulence model with the Upwind Difference convection scheme and an unstructured hybrid mesh with arbitrary matching method were applied to the simulation. The comparing air flow characteristic of the basic HVAC module and total HVAC module with blower were discussed in the paper.

• 대한기계학회논문집B
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• 제30권4호
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• pp.320-327
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• 2006

The computations of chemically reacting laminar and turbulent flows are performed using the preconditioned Navier-Stokes solver coupled with turbulent transport and multi-species equations. A low-Reynolds number $k-\varepsilon$ turbulence model proposed by Chien is used. The presence of the turbulent kinetic energy tenn in the momentum equation can materially affect the overall stability of the fluids-turbulence system. Because of this coupling effect, a fully coupled formulation is desirable and this approach is taken in the present study. Choi and Merkle's preconditioning technique is used to overcome the convergence difficulties occurred at low speed flows. The numerical scheme used for the present study is based on the implicit upwind ADI algorithm and is validated through the comparisons of computational and experimental results for laminar methane-air diffusion flame and $ H_2/O_2$ reacting turbulent shear flow. Preconditioning formulation shows better convergence characteristics than that of non-preconditioned system by approximately five times as much.

• Wind and Structures
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• 제17권3호
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• pp.245-262
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• 2013

The flow interaction between two identical neighboring twin square prisms in a staggered arrangement in an open terrain was investigated experimentally. The downwind prism was mounted on a rigid-aeroelastic setup in an open-terrain boundary layer flow to measure its acrosswind root-mean-square responses and aerodynamic damping ratios. By varying the relative location of the upwind prism and the Scruton number associated with the downwind prism, the acrosswind aeroelastic behavior of the downwind prism was analyzed and compared to that of an isolated one. Results showed that the acrosswind root-mean-square response of the downwind prism could be either suppressed or enhanced by the wake flow produced by the neighboring upwind prism. Besides the assessment of the wake effect of the downwind prism, finally, regressed relationships were presented to describe the variation of the aerodynamic damping ratio so as to predict its acrosswind fluctuating response numerically.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.163-167
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• 2007

For numerical analysis of a tidal flow, a two-dimensional hydrodynamic model is developed by solving the nonlinear shallow-water equations. The governing equations are discretized explicitly with a finite difference leap-frog scheme and a first-order upwind scheme on adaptive hierarchical quadtree grids. The developed model is verified by applying to prediction of tidal behaviors. The calculated tidal levels are compared to available field measurements. A very reasonable agreement is observed.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1998년도 춘계 학술대회논문집
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• pp.162-167
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• 1998

A computer code has been developed for the analysis of 2D viscous flow with free surface. VOF method and higher order upwind scheme have been employed for the accurate prediction of free surface motion. Surface tension effect and axisymmetric flow can be computed by the present code.

• Ocean Systems Engineering
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• 제12권3호
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• pp.359-384
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• 2022

We develop in this work a new well-balanced preserving-positivity path-conservative central-upwind scheme for Saint-Venant-Exner (SVE) model. The SVE system (SVEs) under some considerations, is a nonconservative hyperbolic system of nonlinear partial differential equations. This model is widely used in coastal engineering to simulate the interaction of fluid flow with sediment beds. It is well known that SVEs requires a robust treatment of nonconservative terms. Some efficient numerical schemes have been proposed to overcome the difficulties related to these terms. However, the main drawbacks of these schemes are what follows: (i) Lack of robustness, (ii) Generation of non-physical diffusions, (iii) Presence of instabilities within numerical solutions. This collection of drawbacks weakens the efficiency of most numerical methods proposed in the literature. To overcome these drawbacks a reformulation of the central-upwind scheme for SVEs (CU-SVEs for short) in a path-conservative version is presented in this work. We first develop a finite-volume method of the first order and then extend it to the second order via the averaging essentially non oscillatory (AENO) framework. Our numerical approach is shown to be well-balanced positivity-preserving and shock-capturing. The resulting scheme could be seen as a predictor-corrector method. The accuracy and robustness of the proposed scheme are assessed through a carefully selected suite of tests.

• 한국항공우주학회지
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• 제31권2호
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• pp.10-16
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• 2003

초음속 유동장에서 비정상 직열배치공동 유동 연구를 Navier-Stokes 방정식과 k-$\varepsilon$난류모델을 이용하여 수치 모사하였다. 공동주위의 비정상유동은 자유 전단층과 공동 내부 유동의 상호 작용에 의한 주기성으로 특정지어진다. 수치적 방법은 van Leer의 유량한계계수를 이용한 유량벡터분리법에 기반을 둔 TVD방법을 사용하였다. 먼저, 단일 공동에 대한 압력비 그래프를 통한 주진동 주파수를 비교하였다. 직열배치공동유동에서는 전후방 공동을 몇가지 세장비로 조합하여, 전방 공동의 영향에 의한 후방 공동 유동장의 주진동 주파수 특성등을 분석하였다. 전방공동의 세장비가 작은 경우에는 강한 전방공동의 전단층이 후방공동의 전단츨과 합하여 하나의 전단층 특성을 줌으로 전후방 공동의 주진동특성이 비슷하게 나타나고, 전방공동의 세장비가 큰경우에는 전방공동의 전단층이 확산되면서 내부에 후방공동의 전단층이 발생함으로 주진동수의 특성이 다르게 나타나는 것을 볼 수 있었다.

• 한국전산유체공학회지
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• 제8권4호
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• pp.1-5
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• 2003

A Thin-layer Wavier-Stokes equations are applied for the hypersonic flow over blunt bodies with applications to laminar as well as turbulent flows. The equations are expressed in the forms of flux-vector splitting and explicit algorithm. The upwind schemes of Steger-Warming and Van Leer are investigated to predict accurately the heating loads along the surface of the body. A mixed scheme has been presented for the differencing the convective terms and the mixed scheme is found to be less dissipative producing accurate solutions.