http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
비교차격자를 사용한 비압축성 점성유동의 수치해법에 관한 연구
반석호,김형태 忠南大學校 産業技術硏究所 1995 산업기술연구논문집 Vol.10 No.2
Numerical methods based on the primitive variable formulation for calculating the solution of incompressible steady viscous flows using the nonstaggered grid are investigated. The pressure-Poisson equation with the Neumann boundary condition derived from the normal momentum equation is used to guarantee the divergence-free velocity field. Two different discretization schemes for the pressure-Poisson equation are introduced to minimize the errors on the satisfaction of the discrete continuity and to obtain the smooth pressure field. In addition, three different discretization schemes for the convective terms of the momentum equations, are tested to see their effects on the accuracy and the stability of the overall numerical method. Numerical results are presented for the two-dimensional laminar flow of a driven cavity.
Computation of Turbulent Flows around Full-form Ships
Suak-Ho Van,Hyoung-Tae Kim 한국전산유체공학회 1995 한국전산유체공학회 학술대회논문집 Vol.1995 No.-
This paper presents the result of a computational study on the wake characteristics of two tanker models. i.e. HSVA and DYNE hull forms. The focus of the study is on the distributions of axial, radial and tangential velocities of the two hull forms in way of the propeller, especially over the propeller disk. The effect of bilge vortices on the velocity distribution is also concerned. For the computation of stern and wake flows of the two hull forms. the Incompressible Reynolds-Averaged Navier-Stokes(RANS) equations are numerically solved by the use of a second order finite difference method, which employs a four stage Runge-Kutta scheme with a residual averaging technique and the Baldwin-Lomax model. The calculated pressure distributions on the hull surface and the axial, radial and tangential velocity distributions over the propeller disk arc presented for the two hull forms. finally, the result of wake analysis for the computed wake distribution over the propeller disk is given in comparison with those for the experimental wake distribution for the both hull forms.
Numerical Computation of Turbulent Flow over a Backward Facing Step
Suak-Ho Van(반석호),Hyoung-Tae Kim(김형태) 한국해양공학회 1996 韓國海洋工學會誌 Vol.10 No.3
후방 계단(backward facting step) 주위의 난류 유동 특성을 수치 해석을 통해 파악하고자 하였다. 지배방정식은 2차 정도의 유한 차분 기법으로 이산화하였으며 비교차격자계를 사용하여 양해법으로 계산하였다. 난류 모형으로는 이층 모형(two-layer)을 사용하였고 압력-Poisson 방정식을 이용하여 압력과 속도를 연성시켰다. Re=44,000인 경우에 대해 계산 결과로 부터 후방 계단 뒤의 속도 벡터, 유선, 압력 및 속도 분포, 재부착 길이(reattachment length) 등을 실험치와 비교하였다. 본 계산에 사용한 수치 해석 기법은 박리등이 포함된 복잡한 난류 유동 현상을 잘 재현할 수 있음을 확인할 수 있었다.
Investigation on the Powering Performance Prediction for Azimuth Thrusters
Van, Suak-Ho,Yoon, Hyun-Se The Society of Naval Architects of Korea 2002 Journal of ship and ocean technology Vol.6 No.1
Recently, the application of the electric propulsion system becomes popular because of its advantage over conventional propulsion. However, the complicated flow mechanism and interaction around the azimuth thruster are not fully understood yet, and the studies on the powering performance characteristics with azimuth/pod thrusters are now in progress. The experimental method developed in KRISO(Korea Research Institute of Ships & Ocean Engineering) is introduced and the results of the powering performance tests, consisting of resistance, self-propulsion and propeller open water tests for a cable layer with two azimuth thrusters are presented. For the analysis of powering performance with azimuth thrusters, it is necessary to evaluate the thrust/drag for components of a thruster unit, Extrapolation results could differ according to the various definitions of the propulsion unit; that is the pod, thruster leg and/or nozzle can be treated as hull appendages or as part of propulsion unit, The powering performances based on several definitions are investigated for this vessel. The results of the measurements for the 3-dimensional velocity distribution on the propeller plane are presented to understand the basis of the difference in propulsion characteristics due to the propeller rotational directions.
A Computational Study on Turbulent Flow Characteristics around Full-form Tankers
Van, Suak-Ho,Kim, Hyoung-Tae The Society of Naval Architects of Korea 1996 Journal of hydrospace technology Vol.2 No.2
This paper presents the result of a computational study on the wake characteristics of two tanker models, i.e. HSVA and Mystery hull forms. The focus of the study is on the distributions of axial, radial and tangential velocities of the two hull forms in way of the propeller, especially over the propeller disk. The effect of bilge vortices on the velocity distribution is also concerned. For the computation of stern and wake flows of the two hull farms, the incompressible Reynolds-Averaged Wavier-Stokes(RANS) equations are numerically solved by the second order finite difference method, which employs a four stage Runge-Kutta scheme with a residual averaging technique and the Baldwin-Lomax model. The calculated pressure distributions on the hull surface and the axial, radial and tangential velocity distributions over the propeller disk are presented for the two hull forms. Finally, the result of wake analysis for the computed wake distribution over the propeller disk is given in comparison with those for the experimental wake distribution fur the both hull forms.
Backward Facing Step의 층류 유동 수치계산
반석호(Suak-Ho Van),김형태(Hyoung-Tae Kim) 한국해양공학회 1993 韓國海洋工學會誌 Vol.7 No.2
원초변수를 이용한 Navier-Stokes방정식의 수치계산기법을 개발하고, 이를 응용하여 backward facing step의 층류 유동을 계산하였다. 직교좌표계에서의 비압축성 Navier-Stokes방정식을 풀기위해 시간과 공간항을 2차 정도의 유한차분을 사용하여 이산화하였고 비교차 격자계를 사용하여 양해법으로 수치 계산하였다. 운동량방정식과 연속방정식으로 부터 유도된 압력방정식(pressure-Poisson equation)을 이용하여 무발산 조건을 만족시켰다. Backward facing step의 층류 유동을 100≤Re≤1000 범위에 대해서 수치 계산하였으며 실험결과와 잘 일치하는 결과를 구할 수 있었다. 특히 step뒤에서 생기는 박리구간의 길이는 다른 계산결과들보다 실험치에 가까운 값을 얻을 수 있었으며, Re가 600보다 클때는 위쪽 벽에 또 다른 박리 유동이 발생되는 현상이 예측되었다.