RAMPANT를 이용한 충돌모델주위에 유동에 관한 연구

李鳳來,崔成旭 홍익대학교 산업기술연구소 1997 産業技術 Vol.7 No.-

Conventional aerodynamic simulations have been carried out by using Supercomputer and over a hundred thousand grid points. It takes a long CPU time to get a result. So this method has been mainly used as a research and demonstration tool. In this paper a practical aerodynamic simulation for early phases of the automobile design is presented. CFD(Computational Fluid Dynamics) has been able to apply to industrial field in these days. CPU time is shortened and more fine-mesh can be calculated. This new method has been applied to the aerodynamic simulation system a designer has been able to carry out the practical simulation on early designing phase of an automobile.

평판에 충돌하는 제트 유동에 關한 實驗的 硏究

李鳳來 홍익대학교 산업기술연구소 1994 産業技術 Vol.3 No.-

The purpose of this study is to evaluate different processes of the jet flow development with different boundary conditions. In this study, some experiments have been conducted on conventional axisymmetric jet flow of uniform velocity at the outlet to obtain basic data needed. The jet leaving the open end of a considerably long square nozzle and the conventional axisymmetric jet with uniform velocity distribution at the outlet were compared to evaluate their processes of development by measuring the average velocity. turbulance and intermittency factor. It is found the field of flow is classified into three regions, namely, the potential core region, the characteristic decay region and the axisymmetric decay region. The results of the measurements indicated that the momentum is conserved and that the jet flow is similar to a two-dimensional flow in the potential core region and the characteristic decay region. The behavior of the jet flow in the free jet region is almost the same as an axisymmetric jet expanding into infinite surrounding stationary air. In this investigation, several cross-sections were chosen downstream from the outlet to obtain the half-value radius by measuring each velocity distribution. It was found that the half-value radius started to increase linearly from a point of about 10D dowmstream from the outlet. The method treated here can be applied to a jets with any type of the flow condition.

CFD를 이용한 자동차 주위의 수치해석적 유동 연구

李鳳來,陳元宰 홍익대학교 산업기술연구소 2000 産業技術 Vol.10 No.-

Conventional aerodynamic simulations have carried out over a hundred grid point or wind tunnel experiment by using Supercomputer. It takes s long time to get a result. This paper has dealt on flow characteristics of automobile in the flow field. CFD(Computational Fluid Dynamics) has been able to apply to the industrial field in these days. This new method has been applied to the aerodynamic simulation system, a designer has been able to carry out practically on early designing phase of automobile. This paper has been focused on the necessity of rear-spoiler, the peculiarity of aerodynamic drag, and the level of drive safety. A complex wake structure in the immediate rear of the car has been confirmed. The distributions of the surface pressure coefficient are not sensitively dependent on the Reynolds Number.

PDA 환경에서의 3D 게임엔진에 관한 연구

李鳳來,李銀姬 弘益大學校 産業技術硏究所 2004 産業技術 Vol.14 No.-

The development of mobile contents is transferred from 2D to 3D. 3D mobile engines allow 3D games to appear and run on mobile devices, and a variety of contents such as 3D chatting and avatar services has been made available on them. Due to the advance in the performance of mobile devices, they can now run high quality 3D mobile contents that could be run on only PCs or workstations a few years ago. We are interested in 3D mobile game engines, especially for PDAs. In this paper, we survey and present the core technology of 3D mobile game engines, and 3D game engines which are currently available for PDA devices.

Fluent를 이용한 고속전철주위의 수치해석적 유동연구

李鳳來,진원재 홍익대학교 산업기술연구소 2001 産業技術 Vol.11 No.-

The aerodynamic charateristics of high speed train can be improved by fore-body design. In this paper, the design a fore-body shape which has optimal aerodynamic charateristics, 9 models of fore-body shape are proposed and the change of aerodynamic charateristics is studied through calculations of flow field around high speed train for each fore-body shape. The flow field around high speed trains are calculated using Navier-Stokes equation. The variational trends of aerodynamic charateristics are studied from the result of flow calculations around high speed trains for 9 fore-body shapes. and The three-dimensional unsteady compressible Navier-Stokes equation solver with sliding moving mesh method has been applied to analysis the flow field around the high speed train which is entering into tunnel. From the present study, the generation of compression wave was observed ahead of the train in the from of plane wave and the high pressure in the gap between the train.

분류의 확산에 관한 실험적 연구

李鳳來 홍익대학교 산업기술연구소 1996 産業技術 Vol.6 No.-

As a problem in industrial application, there is always the question of turbulent transport of heat, mass or momentum in instances as gas burner, the combustion chamber using fluid or atomized coal, drying by jet, and the ejector, which has been the object of industrial research. The purpose of this study is to evaluate different processes of development of jet flow with different boundary conditions. In this paper, some experiments have been conducted on conventional axisymmetric jet flow of uniform velocity at the outlet for the purpose of obtaining such basic data needed in further investigation. From the observed center velocity it is found that the field of flow is classified into three regions namely, the potential core region, the characteristic decay region and the axisymmetric decay region. The results of the measurements have indicated that the momentum is conserved and that the jet flow is similar to a two-dimensional flow in the potential core region and the characteristic decay region. On the other hand, the impingement of a jet flow on a solid surface is and interesting subject of enginnering in such instances as point spraying, jet drying processes, gas welding, and particularly the exhaust gas of the VTOL aircraft. In this inverstigation, several cross-section were chosen downstream from the outlet to obtain the half-value radius by measuring each velocity distribution. It was found that the half-value radius started to increase linearly from a point of about 10D downstream from the outlet. The method treated here can be applied to jets with any type of the flow condition.

유동장내 다각형 모델의 유동 해석

李鳳來 홍익대학교 산업기술연구소 2003 産業技術 Vol.13 No.-

The purpose of this experiment is observation about the flow field change close to the surface of polygon models. We connect pitot tubes at regular intervals with travers from the surface of polygon models. We install 3 different polygon models that are the posts of circle and hexagon and octagon. We gave each variable main flow, shape of the polygon models and then take the data from pressure hole by using tube-manometer and micro-manometer. We observe datas by flow at eacj surface with pressure difference and velocity change on the surface of polygon models. We see pressure difference according to velocity change by using data here.

자동차 후미 정상이 유동에 미치는 영향에 관한 실험 및 수치해석적 연구

李鳳來 홍익대학교 산업기술연구소 1999 産業技術 Vol.9 No.-

This paper has dealt on flow characteristics of model around in the flow field by using circular cylinder skin-pressure measurement, the effect and inspection of rear-spoiler on cad, simulation and flow visualization. By using wind tunnel, simulation and smog generator, this paper has went on study, and has put a lot of attention to do experiment laminar condition on flow filed. When flows dragged as a form of laminar clash with the mode, flows around the model are changed as turbulent, wake, and separation fields, as a result. After this, to make it sure, I checked the separation field by taking circular cylinder as a model, and then adjusted this to a car for checking the effect of rear-spoiler. This document has been focused on the necessity of rear-spoiler, the peculiarity of aerodynamic drag, and the level of drive safety. Additionally, I analyzed flow type of circular cylinder and rear-spoiler through flow visualization using smog generator.

공기역학적 항력특성에 대한 실험적 연구

李鳳來,崔成旭 홍익대학교 산업기술연구소 1998 産業技術 Vol.8 No.-

We install various model in test section of wind tunnel. With constant velocity, we give each variable distance and then take data from pressure holl by using Micro-Manometer and observe pressure difference of body's surface and see real-body flowtype by using smogwrite method with scanning point based on flow type's size. We connect pitot tube with travers. We see pressure difference of surrounding body moving travers up-down and see flow property accoding to pressure difference by using data here

자동차 주위의 유동구조에 대한 수치 해석적 연구

李鳳來 홍익대학교 산업기술연구소 2002 産業技術 Vol.12 No.-

Conventional aerodynamic simulations have carried out over a hundred grid point or wind tunnel experiment by using Supercomputer. It takes a long time to get a result. This paper has dealt on flow characteristics of automobile in the flow field. Fluent has been able to apply to the industrial field in these days. This new method has practically on early designing phase of automobile. This paper has been focused on the necessity of rear-spoiler, the peculiarity of aerodynamic drag, and the level of drive safety. A complex wake structure in the immediate rear of the car has been confirmed. The distributions of the surface pressure coefficient are not sensitively dependent on the Reynolds Number.