• Title/Summary/Keyword: 전산 유체역학

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An Efficient Method for Estimating Optimal Path of Secondary Variable Calculation on CFD Applications (전산유체역학 응용에서의 효율적인 최적 2차 변수 계산 경로 추정 기법)

  • Lee, Joong-Youn;Kim, Min Ah;Hur, Youngju
    • The Journal of the Korea Contents Association
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    • v.16 no.12
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    • pp.1-9
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    • 2016
  • Computational Fluid Dynamics(CFD) is a branch of fluid mechanics that solves partial differential equations which represent fluid flows by a set of algebraic equations using computers. Even though it requires multifarious variables, only selected ones are stored because of the lack of storage capacity. It causes the requirement of secondary variable calculations at analyzing time. In this paper, we suggest an efficient method to estimate optimal calculation paths for secondary variables. First, we suggest a converting technique from a dependency graph to a ordinary directed graph. We also suggest a technique to find the shortest path from any initial variables to target variables. We applied our method to a tool for data analysis and visualization to evaluate the efficiency of the proposed method.

Simulation of Solid Particle Sedimentation by Using Moving Particle Semi-implicit Method (고체 입자형 MPS법을 이용한 토사물 퇴적 시뮬레이션)

  • Kim, Kyung Sung;Yu, Sunjin;Ahn, Il-Hyuk
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.1
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    • pp.119-125
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    • 2018
  • The particle based computational fluid dynamics (CFD) method, which follow Lagrangian approach for fluid dynamics, fluid particle behavior by tracking all particle calculation physical quantities of each particle. According to basic concept of particle based CFD method, it is difficult to satisfy continuum theory and measure influences from neighboring particle. Article number density and weight function were used to solve aforementioned issue. Difficulties continuum mean simulate non-continuum particles such as solid including granular and sand. In this regard, the particle based CFD method modified solid particle problems by replacing viscous and surface tension forces friction and drag forces. In this paper, particle interaction model for solid particle friction model implemented to simulate solid particle problems. The broken dam problem, which is common to verify particle based CFD method, used fluid or solid particles. The angle of repose was observed in the simulation results the solid particle not fluid particle.

Numerical Modelling Techniques of VPMM for Manta Type UUV (만타형 UUV의 VPMM 전산해석기법 개발)

  • Sang-Eui Lee
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2023.05a
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    • pp.151-151
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    • 2023
  • An accurate prediction of the hydrodynamic maneuvering darivatives is essential to desing a robust control system of a UUV(unmanned underwater vehicle). Typically, these derivatives were estimated by either the towing tank experiment or semi-empirical methods. With the enhancement of high performance computing capacity, a numerical analysis using computational fluid dynamics has reach the level of experiment. Therefore, the aims of the present research are to numerically develop a computational model for the vertical planar motion mechanism of a UUV and to estimate the hydrodynamics loads in 6-DOF. The target structure of the present study was manta type UUV (12meter length). The numerical model was developed in 1/ 6 model scale. Numerical results were compared with the results of the towing tank experiment for validation. In the present study, a commercial RANS-based viscous solver STARCCM+ (ver 17.06) was used.

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Application of MSAP to JDAM Separation from an F/A-18C Aircraft (MSAP을 이용한 F/A-18C로 부터 JDAM 분리 해석)

  • Lee Seungsoo
    • Journal of computational fluids engineering
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    • v.9 no.1
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    • pp.41-47
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    • 2004
  • A successful store separation analysis tool, MSAP(Multi-body Separation Analysis Program) has been applied to F/A-18C/JDAM CFD Challenge Ⅱ. The challenge was devised to challenge CFD community to use CFD methodologies to predict and match the trajectory of a JDAM MK-84 separating from F/A-l8C. Trajectory simulations for two flight conditions were performed. Comparison between computed and measured flight trajectories for both conditions shows a good agreement.

Drag Prediction of Elliptic Airfoil (타원형 에어포일의 항력 예측)

  • Kim C. W.;Park Y. M.;Kwon K. J.;Lee J. Y.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.03a
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    • pp.23-26
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    • 2004
  • Drag prediction is sought for the aifoil having laminar and turbulent flow characteristics with CFD code being unable to predict transition to turbulent flow. Laminar flow simulation presents some insight to the transition position. Separate simulations with laminar and turbulent flow and their combination estimate the drag of the airfoil containing laminar and turbulent flow characteristics.

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Unsteady flow analysis of KSR-III pressurization system (KSR-III 가압 시스템에 대한 비정상 유동해석)

  • Jung T. K.;Jung Y. S.;Oh S. H.;Lee D. S.
    • 한국전산유체공학회:학술대회논문집
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    • 2001.05a
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    • pp.116-120
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    • 2001
  • The impactive Pressure wave induced by pyro valve in the pressurization system of KSR-III may result in fatal failure or malfunction of valves, so it is important to know the pressure wave characteristic in the pressurization system. An unsteady flow analysis in the simplified pressurization system was peformed by Finite difference method.

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ANALYSIS OF FLOW CHARACTERISTIC FOR CONE DISC TYPE CONTROL VALVE (콘 디스크 형 컨트롤 밸브의 유동특성 연구)

  • Ko, S.H.;Kwack, Y.K.;Lee, S.H.;Kang, M.K.
    • 한국전산유체공학회:학술대회논문집
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    • 2007.10a
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    • pp.177-180
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    • 2007
  • A three dimensional numerical analysis has been made for the cone disk control valve and the flat disk control valve. The simulation of the incompressible flow in the each control vale are performed by using the commercial code. Six flow cases of each control valve are investigated.

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