• Economic and Environmental Geology
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• v.44 no.2
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• pp.153-159
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• 2011

A comprehensive mechanistic model has been used to determine the flow pattern for gas-oil two-phase flow in pipes of petroleum production system. Depending on operational parameters, geometrical variables, and physical properties of the two phases, the two phases shows a specific flow patterns. For different parameters of the system, How pattern were compared for wide range of superficial velocities of oil and gas. In a variety of parameters, the inclinational angle and superficial velocities of oil and gas are the most dominant factors in determining the flow patterns for two-phase flow in pipelines. Other parameters such as pipe diameter and fluid properties have a limited effect on the change of flow patterns except for near transition. The mechanistic model is shown to be useful to determine the flow pattern in situations where either an experimental evaluation in a laboratory or reliable correlations are not available.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.7-7
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• 1998

액체 연료 분포의 균일성과 대칭성은 연소 효율을 높이고, 공해 물질을 줄이는데 있어서 필수적인 요소이기 때문에 분무 패턴을 정량적으로 해석하는 것은 매우 중요하다. 고전적으로 사용되고 있는 mechanical patternator는 ⅰ) 유동을 교란시키고, ⅱ) 공간 분해능이 떨어지며, ⅲ) 복잡한 재순환 유동이나 화학 반응이 있는 유동에서의 적용이 어렵다는 단점을 가지고 있다. 이러한 단점들을 극복하기 위하여 레이저를 이용한 optical patternator에 대한 연구가 진행되고 있다. Optical patternator는 유동을 교란시키지 않으면서 고해상도의 분무 패턴 측정을 할 수 있다. 형광 신호는 물질의 체적에 비례한다. 따라서, 레이저 평면광을 분무에 조사시켜 주어서 유도되는 형광 신호를 이용하는 평면액체 레이저 유도 형광법(PLLIF : Planar Liquid Laser Induced Fluorescence)은 분무패턴을 알아보는 매우 유용한 방법이다.

• Journal of Internet Computing and Services
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• v.21 no.1
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• pp.71-78
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• 2020

Recently, as the issue of gentrification emerges, it becomes important to understand the dynamics of local commercial district, which plays the important role for facilitating the local economy and building the community in a city. This paper attempts to provide the framework for systemically analyzing and understanding the local commercial district. Then, this paper empirically analyzes the patterns of sales and flow of floating population by focusing on two representative local commercial districts in Seoul. In addition, the floating population data from telecommunication bases is further modeled with Markov chain for systemically understanding the local commercial districts. Finally, the transition patterns and consumption amounts of floating population are comprehensively analyzed for providing the implications on the evolutions of local commercial districts in a city. We expect that findings of our study could contribute to the economic growth of local commercial district, which could lead to the continuous development of city economy.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.1
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• pp.37-46
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• 2017

Thermal Marangoni flow has been observed inside droplets on heated surfaces, finally resulting in a coffee stain effect. This study aims to visualize and control the thermal Marangoni flow by employing periodic vertical vibration. The variations in the contact angle and internal volume of the droplet as it evaporates is observed by using a combination of continuous light and a still camera. With regard to the internal velocity, the particle image velocimetry system is applied to visualize the internal thermal Marangoni flow. In order to estimate the internal temperature gradient and surface tension on the surface of a droplet, the theoretical model based on the conduction and convection theory of heat transfer is applied. Thus, the internal velocity increases with an increase in plate temperature. The flow directions of the Marangoni and gravitational flows are opposite, and hence, it may be possible to control the coffee stain effect.

• Journal of the Korean Society for information Management
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• v.30 no.4
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• pp.93-110
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• 2013

During the last decade, increasing use of technology that facilitates information access has changed academic library services. The emergence of information commons is one of the key changes. Most previous studies on information commons have focused on its conception and role. Whereas, considering information commons as a spatial service, this study aims to examine the influence of information commons on user traffic patterns within the library and perception of the library. As the information commons grew into main library service space and facility, it is necessary to explore what influences information commons have on the behavior and recognition of users. Two methods were used. First, observation method was used to record traffic pattern and user behavior. Second, twenty undergraduates and twelve graduates were interviewed regarding the use and recognition of the information commons and the library. The results of the study show that the traffic patterns were different between undergraduate students and graduate students; the location and structure of facilities influences their movement and behaviors; and the recognition of information commons tends to affect the perception of the entire library. The findings may help librarians improve and plan for library spaces to meet user demands.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.189-196
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• 2012

The heavy moderator acts as the ultimate heat-sink in an operating CANDU reactor. HUKINS has been developed to investigate moderator flow patterns. HUKINS consists of a 38.4-mm-thick cylindrical shell with a 0.95 m inner diameter and 88 sus-tubes that produce a total heat of 10 kW. A chemical visualization method was selected to estimate the occurrence of typical moderator flow patterns. Momentum-dominated flow, mixed flow, and buoyancy-dominated flow are detected under conditions of a heat load of 7.7 kW and input mass flow rates of 4, 7, and 11 L/min. The experimental results are similar to the results of a CFD simulation that consisted of approximately 1.9 million grids and was conducted using the k-${\varepsilon}$ turbulence model. Therefore, both the present experiments and simulations using HUKINS, a 1/8-scale model, represent all three important flow patterns expected in the real CANDU6 reference reactor. Thus, it has been demonstrated that HUKINS could be useful in the study of CANDU6 moderator circulation.

• Computational Structural Engineering
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• v.32 no.4
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• pp.4-10
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• 2019

• Journal of the Korean Geographical Society
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• v.37 no.1
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• pp.15-40
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• 2002

This study is an attempt to grasp the spatial patterns and characteristics in the freight flows based on freight quantity data in 1997. The spatial background for the study is the Capital Region, which plays an important role in regional economics and industrial development. The methodology in the research used factor analysis to produce a functional region. The study selected three categories of freight that account for more than 60 percent of freight flows, chemical industrial goods, light industrial goods, and metal machinery industrial goods. The target analysis unit is divided into 36 zones. The common characteristic of the three categories is that they are concentrated at one specific region than are dispersed regionally. And in particular, the remarkable feature is that the central region of the study is Seoul. Usually the eminent regions of nows were made where environment of distribution facilities is good but these were made in a less than good environment. I think a reason is that facilities were uneven distribution.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.1-9
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• 2004

The flow in the LOX manifold of liquid rocket (KSR-III) has been analyzed using a CAE technique with an objective of modeling injector orifices in order to reduce the computational cost for the flow analysis without much losing the accuracy of capturing the flow physics. The numerical result shows that the flow just above the injector orifices is not uniformly distributed in terms of pressure and mass flow rate in case pre-distributors are not equipped inside the manifold. This non-uniformity of mass flux is attributed to the presence of large-scale flow patterns. Several boundary conditions which were designed to effectively replace the presence of injector orifices have been tested and it was found that a simple modeling can be possible by mimicking the actual shape of the orifices.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.582-584
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• 2003

본 논문은 수중에서 유동하는 입자의 움직임을 추적하고 유체의 흐름에 따라 분산되는 입자의 분산정도 그리고 입자의 침강패턴을 분석하기 위한 계산형 3차원 시스템을 제안한다. 이러한 계산형 시스템은 물과 같은 공간에서 움직이는 입자들을 고려하고 있는데, 물의 흐름을 위해 운동량방정식과 연속방정식을 일반화하여 흐름을 제어하고 있다. 또한 물이라는 공간 특성을 고려하여, 입자간에 작용하는 부력, 침강력등의 물리적인 힘을 적용시키고 있다. 이렇게 제안된 시스템을 통해 다양한 외부적 요인에 따라 움직임을 달리하는 유동 입자들은 실제 울에서와 같이 유사하게 가시화되도록 한다. 이렇게 가시화된 유동 입자의 움직임을 추적하여 입자들의 침전패턴까지도 미1리 예측해 낼 수 있게 된다.