• Tribology and Lubricants
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• v.29 no.1
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• pp.39-45
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• 2013

Magnetorheological (MR) fluid belongs to the group of smart materials. In MR fluid, iron particles in base oil form chains in the direction of the applied magnetic field, thus resulting in a variation in the stiffness and damping characteristics of the fluid. Research is being carried out on controlling the stiffness and damping characteristics as well as the tribological characteristics of the MR fluid. In this study, the friction characteristics of MR fluid have been evaluated using three types of materials and magnetic fields of different strengths. The coefficients of friction of the three types of MR fluid are measured, and the relationship between the coefficient of friction and the strength of the applied magnetic field is obtained.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.74-74
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• 2003

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.233-234
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• 2003

Fly ash enters axial compressor when a turbomachinery is operated in an adverse environment. We have numerically investigated erosion of the blade and shroud in the turbulent compressor passage flow under the influence of gas-particle two-phase interaction. There have appeared quasi-three dimensional calculations on this subject but not the complete three-dimensional gas-particle interaction as done in the present work. Lagrangian particle tracing technique is used on the base of parallel processing for efficient calculation. Accuracy of the present code is tested using the benchmark lPL nozzle. In the DFVLR compressor blades, we have shown that a large number of particles passing through the tip clearance make impact on the blade tip and on the shroud. Higher degree of erosion is resulted by the heavier particles due to the centrifugal force.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.203-204
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• 2003

Fly ash enters axial compressor when a turbomachinery is operated in an adverse environment. We have numerically investigated erosion of the blade and shroud in the turbulent compressor passage flow under the influence of gas-particle two-phase interaction. There have appeared quasi-three dimensional calculations on this subject but not the complete three-dimensional gas-particle interaction as done in the present work. Lagrangian particle tracing technique is used on the base of parallel processing for efficient calculation. Accuracy of the present code is tested using the benchmark JPL nozzle. In the DFVLR compressor blades, we have shown that a large number of particles passing through the tip clearance make impact on the blade tip and on the shroud. Higher degree of erosion is resulted by the heavier particles due to the centrifugal force.

• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.67-72
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• 2007

A post-processing program based on the OOP(Object-Oriented Programming) concept has been developed for visualization of MRI. User-friendly GUl(Graphic User Interface) has been built on the base of MFC(Microsoft Foundation Class). The program is organized as modules by classes based on VTK-library, and these classes are made to function through inheritance and cooperation which are an important and valuable concept of object-oriented programming. The major functions of this post-processor program are introduced and demonstrated, which include contour plot, surface plots, cut plot and clip plot as well as view manipulation (translation, rotation, scaling etc).

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.28-31
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• 2010

In order to clarify the characteristics of power performance and uncertainty of a wind turbine, an investigation was performed in Hangyeong wind farm, Jeju island, Korea. Data were collected for 12 months from Feb. 2, 2008 to Jan. 1, 2009. This study was conducted on the base of the International standard, and observed the methods of mesurement and evaluation form IEC 61400-12. As a result, power performance curve was calculated by measured data and compared with the sixth unit of VESTAS V90-3.0MW in Hangyeong wind farms. In consequence of this paper, uncertainty was estimated from 7% to 14% on the range of the average wind speed from 4m/s to 11m/s.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.78-82
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• 2010

An integrated multi-disciplinary design system plays a critical role in the preliminary design of an aircraft. In this paper such system is developed for the multi-disciplinary computation and design; aerodynamics elasticity, and radio frequency stealth. Common data base of geometry and structured grids is generated and used for aerodynamic, structural and eletromagnetics analysis. The Navier-Stokes CFD, FEM, and CEM technique are used for aerodynamic, structural, and RF stealth computations respectively.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.193-196
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• 2004

Numerical optimization method of long endurance airfoil has been performed with a RSM(Response Surface Method) for smart UAV wing design. For the base line airfoil, NACA 64621 airfoil was selected and optimized to satisfy long endurance condition for smart UAV Aerodynamic coefficients required for RSM are obtained by using 2-D Navier-Stokes solver with Spalart-Allmaras turbulence model. The optimized airfoil showed increased maximum lift and endurance factors together with reasonable thickness ratio.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10a
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• pp.21-24
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• 2002

There is a trend with driveline lubricants toward improved thermal stability, vehicle component durability and fuel efficiency. These improvements can significantly reduce vehicle operating costs and improve customer satisfaction. Of these improvements, the fuel efficiency is getting a substantial attention due to recent focus on $CO_2$ emission control in Europe, Japan and $CAF{\'{E}}$ requirement in U.S.A. Lower viscosity axle oils and transmission fluids are currently being evaluated as potential solutions since these lubricants tend to reduce the churning losses and can improve the fuel efficiency. However, these lubricants should provide adequate gear and bearing protection, while increasing the overall efficiency of the driveline components. In this paper, the development of new fuel efficient axle was discussed with the focus on the effect of base oils, additives, and viscosity modifiers on the fuel efficiency of driveline components.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.249-251
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• 2011

International energy agency(IEA) consisted of OECD countries deals with international energy problems. IEA/Wind ExCo is an execution committee under IEA for the implementing agreement for co-operation in the research, development and deployment of wind energy systems. Currently 22 countries participate the committee and 11 research tasks are in progress. 11 tasks are base technology information exchange, wind energy in cold climates, offshore wind energy technology deployment, integration of wind and hydropower systems, power systems with large amounts of wind power, cost of wind energy, labelling small wind turbines, social acceptance of wind energy projects, MexNext aerodynamics and comparison of dynamic computer codes and models, offshore wind energy and wakebench. At the presentation, activities of major wind energy countries and IEA/Wind ExCo and research tasks are introduced.