• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.775-780
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• 2008

This paper reports on the internal flow of a centrifugal mini pump working at the low flow rate operating conditions. The RNG $\kappa-\varepsilon$ turbulence model was employed to simulate the three-dimensional turbulent flow in the pump. To examine and certify the simulation results, a transparent acrylic centrifugal mini pump model which is suitable for PIV measurement has been developed. The tongue region and the passages region between blades were investigated using PIV. In order to eliminate the effect of refraction on the area closed to the wall and increase the measurement accuracy, the fluorescent particles were scatted into the working fluid with the tracing particles. It is found from the calculation and PIV measurement results that there is a large area of recirculation flow near the tongue at low flow rate operating conditions. The computationally predicted water head using the $\kappa-\varepsilon$ turbulence model at low flow rate operating conditions are in very good agreement with the experimentally measured water head and the mean velocity distributions at investigation area obtained by PIV and calculation showed a satisfactory agreement as well. Meanwhile, the results of PIV measurements show that the flow status in one passage is different to another. And for capturing the internal flow detail information, the $\kappa-\varepsilon$ turbulence model is not very suitable.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.95-97
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• 1996

Circular coils are widely used in electromagnetic applications, and the force in a sets of coils consisting of more than two can be divided into three components. Among them, one component called radial force is acting on the radial axis, and it is exposed as stree or impact. Calculation of the radial force was used to be performed by introducing Ampear's law of force which is $F=J{\times}B$. However, many cases in analyzing a system, calculation method from the mutual inductance between the coils is oftenly employed to get the axial force and resulting dynamics. In this case, if the calculation of radial force from the mutual inductance is possible, flow of the calculation for the system analysis would be much more simpler.

• Journal of Advanced Marine Engineering and Technology
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• 제29권1호
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• pp.86-97
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• 2005

Nowadays, Water Mist Fire Extinguishing System is increasingly used in maritime field for various application. The fire extinguishing capability of the system should be verified by hydraulic calculation in the same manner as the conventional water based fire extinguishing system such as sprinkler system. water spray system and etc. Additionally, the review of effectiveness of friction loss calculation method used for hydraulic calculation is needed because the pipe flow characteristic of its piping system has higher Reynolds number than that of the conventional system. In this paper the review work was carried out based on the NFPA Code 750.

• 조명전기설비학회논문지
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• 제29권7호
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• pp.14-21
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• 2015

Distribution systems are operated in radial structure, but temporal loop structure could be founded the live load transfer. Main purposes of reconfiguration of distribution network are load balancing, loss minimization and voltage drop maintaining. In the loop structure, huge loop current can be flowed between two substations in case of large voltage angle difference. Protection devices of distribution line can be triped by this huge loop current. So, precise calculation of loop current is very important for secure switching. This paper proposes a novel calculation method of loop current using the voltage angle differences measured at the tie switches. Feasibility of the propose method has been verified by various case studies based on Matlab simulation.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.187-193
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• 2011

In this report, We compared the actual test with the result of pow calculation and Resistance/Self-propulsion of the ship using STAR-CCM+ which is the commercial Reynolds Averaged Navier-Strokes(RANs) Solver. The calculation model was the KRISO Container Ship and 205K Bulk Carrier of Sungdong shipbuilding company. For this calculation, We used Realizable K-Epsilon model for flaw analysis, VOF method for the free surface creation, Moving Reference Frame method for reducing the POW calculation time, and Sliding Mesh method for Self-Propulsion analysis. Calculation of Resistance and Self-Propulsion includes the free-surface. And all calculations in this report were based on unstructured grids.

• 한국항행학회논문지
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• 제14권2호
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• pp.161-169
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• 2010

최근 항공교통량의 증가에 따라 보다 효율적인 항공교통흐름제어가 요구되고 있다. 이에 본 논문에서는 효율적인 항공관제를 위하여 항공기의 흐름을 유연하게 하기 위한 알고리즘 기법을 연구하였다. 항공교통 환경은 일반 교통 환경과는 다르게 항공기 기종에 따른 수평 및 수직 분리 간격이 존재한다. 빈센티 공식을 이용하여 항로의 거리를 산출하고 다익스트라 알고리즘을 이용하여 항로의 거리에 교통량을 적용하여 가중치를 생성하고 이를 이용하여 항공기가 연료 및 시간의 낭비를 최소화하는 항로를 선택하도록 하였다. 성능평가 결과 기존의 항로 연산 알고리즘의 단순한 최단항로 산출과는 달리 제안된 알고리즘은 교통량 파악을 통한 최적항로를 선택함으로써 효율적으로 항공교통관제를 할 수 있음을 확인하였다.

• Tribology and Lubricants
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• 제20권5호
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• pp.284-291
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• 2004

We present a three-dimensional average flow model considering elastic deformation of pad asperities for chemical mechanical planarization. To consider the contact deformation of pad asperities in the calculation of the flow factor, three-dimensional contact analysis of a semi-infinite solid based on the use of influence functions is conducted from computer generated three dimensional roughness data. The average Reynolds equation and the boundary condition of both force and momentum balance are used to investigate the effect of pad roughness and external pressure conditions on film thickness and wafer position angle.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.140-145
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• 2000

The objective of experimental study is to apply simultaneous measurement by PIV(Particle Image Velocimetry) to high_speed flow characteristics within ginseng cleaner model. Three different kinds of flow rate(15.20 27ℓ/min) are selected as experimental condition. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. The instantaneous velocity distribution time0mean velocity distribution and velocity profile are represented quantitatively for the deeper understanding of the flow characteristics in a ginseng cleaner model.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.258-259
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• 2003

Flow around Savonius rotor is studied by means of the numerical simulation. Three-dimensional incompressible Navier-Stokes equations are solved numerically. Overgrid system is employed in order to enable the flow calculation of complex geometry. The basic equations in each region are solved by using the standard MAC method. The physical quantities such as the velocity and the pressure among each region are transferred through the overlapping region which is common in each region. Some numerical results of static and rotating rotor will be presented.

• 한국전산유체공학회지
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• 제5권1호
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• pp.22-26
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• 2000

The flow around a ship is complex, especially, at the stern region of a full ship, where highly curved streamlines, hook-shaped iso-velocity contours, and strong secondary flow exist. To resolve this complex flow, an Algebraic Stress Model(ASM) is applied. The calculations are performed for the HSVA Tanker. The results are improved comparing with those of standard k-ε turbulence model, but still show a little difference from the experiments.