• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.506-507
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• 2005

• 한국멀티미디어학회논문지
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• 제12권2호
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• pp.323-328
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• 2009

게임이나 가상현실 등에서 사용자들에게 사실성과 몰입 감을 주기 위해서 자연 현상들을 시뮬레이션하고 있다. 게임이나 가상현실에서 물이나 바다와 같은 유체를 3차원으로 시뮬레이션 하는데 있어서 중요한 요소는 실시간 처리와 사실성이다. 유체 모델은 특정 상황에 따른 다양한 방정식과 많은 파라미터 값에 의해 제어되기 때문에 시뮬레이션 하는데 많은 어려움이 따른다. 또한 복잡한 물리 수식을 기반으로 하기 때문에 유체 모델을 시뮬레이션하기 위해서는 많은 수행 시간이 소요된다. 본 논문에서는 실시간 유체와 강체(rigid body) 사이의 상호작용을 표현하기 위해 간략화 된 유체 표면 모델(Fluid-Surface Model)을 제안하고, 개선된 계산과정을 통해 보다 빠르게 시뮬레이션 하도록 한다. 또한 본 논문에서는 유체의 표면과 강체의 상호작용을 표현하는데 있어서 유체의 항력에 의해서 강체와 충돌 시 발생하는 유체 표면의 움직임을 나타낸다. 본 논문에서 제안하는 자연스러운 유체 표면 모델은 유체역학적 방법을 사용하여 실시간에 사실적으로 표현된다. 그리고 이러한 유체 표면 모델을 PC 환경에서 사용자와 상호작용 가능하도록 재현하여, 게임이나 애니메이션에서의 유체 모델들에도 적용할 수 있다.

• Design & Manufacturing
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• 제13권3호
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• pp.12-18
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• 2019

Fluid jet polishing is a method of jetting a fluid to polish a concave or free-form surface. However, the fluid jet method is difficult to form a stable polishing spot because of the lack of concentration. In order to solve this problem, MR fluid jet polishing system using an abrasive mixed with an MR fluid whose viscosity changes according to the intensity of a magnetic field is under study. MR fluid jet polishing is not easy to formulate for precise optimal conditions and material removal due to numerous fluid compositions and process conditions. Therefore, in this paper, quantitative data on the factors that have significant influence on the machining conditions are presented using various simulations and the correlation studies are conducted. In order to verify applicability of the fabricated MR fluid jet polishing system by nozzle diameter, the flow pattern and velocity distribution of MR fluid and polishing slurry of MR fluid jet polishing were analyzed by flow analysis and shear stress due to magnetic field changes was analyzed. The MR fluid of the MR fluid jet polishing and the flow pattern and velocity distribution of the polishing slurry were analyzed according to the nozzle diameter and the effects of nozzle diameter on the polishing effect were discussed. The analysis showed that the maximum shear stress was 0.45 mm at the diameter of 0.5 mm, 0.73 mm at 1.0 mm, and 1.24 mm at 1.5 mm. The cross-sectional shape is symmetrical and smooth W-shape is generated, which is consistent with typical fluid spray polishing result. Therefore, it was confirmed that the high-quality surface polishing process can be stably performed using the developed system.

• 한국기계가공학회지
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• 제7권2호
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• pp.31-37
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• 2008

In this paper, we analyzed the dynamic behavior of magnetic fluid in a circular pipe with multiple permanent magnets. Magnetic fluid react on magnetic field against the normal fluid. In other words, magnetic fluid flow has the electromagnetism and fluid mechanics. So magnetic fluids has studied about the fluids properties and experiment. In this paper we studied the magnetic fluids velocity and pressure distribution for the novel type actuator. Because the velocity and pressure distribution is the important element of the magnetic fluids flow. First, we analyzed the Maxwell equation for the multiple permanent magnet and then concluded the governing equations for the magnetic fluid flow using the equation of Navier-Stokes. And, we simulated the dynamic behavior of magnetic fluid flow using the FEM(Finite Element Method). And we illustrated the relation between magnetic field and dynamic behavior of magnetic fluid flow.

• Tribology and Lubricants
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• 제14권2호
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• pp.42-48
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• 1998

Electro-Rheological (ER) fluid is a class of functional fluid whose apparent viscosity can be varied by the applied electric field strength. The ER fluid is classified into two types; one is a dispersive fluid and the other is a homogeneous. Dispersive ER fluid is a colloidal suspension of fine semiconducting particles in a dielectric liquid and liquid crystal (LC) is classed as homogeneous type ER fluid. LC has been originally developed for some electronic display devices. Various mechanical components applying ER fluid have been developed, and the their performance typically depends on the characteristics of ER fluid which have generally been evaluated by a rotational viscometer. However, the ER fluid introduced into various mechanical components undergoes not only simple shear flow but press flow or oscillating flow. For the evaluation of ER fluid, the authors developed an reciprocating type viscometer. The amplitude is controlled on 5 mm at the frequency from 50 to 1000 Hz. In the present paper, the performance of several types of ER fluid is evaluated by the reciprocating type viscometer and compared with those evaluated by a rotational viscometer.

• 대한한의학원전학회지
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• 제23권1호
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• pp.11-13
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• 2010

In this article, the concept of body fluid is explained in three aspects: the word meaning of body fluid, the origins of the definitions of the body fluid concept and the connotation and extension of body fluid. Investigating data about the time Hwangjenaegyeong(黃帝內經) was written, the author discovers that the meaning of "Aek(液)" is clear, but there are still questions about the meaning of "Jin(津)". The concept of body fluid derived from observation of life phenomenon and ancient philosophy on the "water". The concept of body fluid should be expressed as that body fluid is a general term for all normal liquids in the body. Within the meridians, as the composition of blood components; outside the meridians, constituting the intrinsic body fluids of various organs and tissues. This is the main part of body fluid, coming from diet, constituting the human body and maintaining human life activities, playing the roles of moistening and nourishing various of organs and tissues of the body. In addition, Interstitial fluid, all kinds of normal liquid secretion and metabolic products, such as sweat, tears, nasal discharge, saliva, slobber, gastric juice, intestinal fluid, urine, joint fluid, latex and so on, both belong to body fluid.

• 유공압시스템학회논문집
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• 제8권4호
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• pp.24-31
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• 2011

Double-color Injection molding machine is the assembly of many kinds of mechanical, fluid power part and electric electronic control system. From in these, fluid power is a part where becomes the first core of this machine. Fluid power systems of double-color injection molding machine are modelled and analyzed using a commercial program AMESim. Partial system models which is divided according to functional operation are made and its analysis results shows how design parameters work on operational characteristics like pressure, flow rates, displacement at each node and so on. Analysis modeling and compared the data which gets from experiment and the analysis result which has a reliability got data. The results made by analysis will be used design of fluid power circuit for developing a double-color injection molding machine.

• 한국소음진동공학회논문집
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• 제22권8호
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• pp.763-770
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• 2012

The free vibration characteristics of fluid-filled cylindrical shells on partial elastic foundations are investigated by an analytical method. The cylindrical shell is fully or partially surrounded by the elastic foundations, these are represented by the Winkler or Pasternak model. The motion of shell is represented by the first order shear deformation theory to account for rotary inertia and transverse shear strains. The steady flow of fluid is described by the classical potential flow theory. The fluid-structure interaction is considered in the analysis. The effect of internal fluid can be considered by imposing a relation between the fluid pressure and the radial displacement of the structure at the interface. To validate the present method, the numerical example is presented and compared with the available existing results.

• 한국정밀공학회지
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• 제22권3호
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• pp.29-37
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• 2005

In this study, the control of the free surface deformation of a magnetic fluid for the change in electromagnetic force is discussed. The free surface of magnetic fluid is formed by the balance of surface force, gravity, pressure difference, magnetic normal pressure and magnetic body force. Magnetic fluid in characteristics of fluid adjusted to the opposite direction of the gravity direction. Thus, the device of a magnetic fluid proposed the complete zero-leakage sealing, oscillator for surface control, boundary layer control, MHD, flow control, flow using magnetic levitation system and surface actuator. This study show the deformation of surface rise due to the intensity of the magnetic field and possibility of two-dimensional control of magnetic fluid through the feedback data of hall sensor.

• 오토저널
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• 제15권1호
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• pp.45-54
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• 1993

The reattachment lengths of the Non-Newtonian fluid are investigated in the sudden expansion pipes whose ratios are 2.316 and 3.368, and the range of the Reynolds numbers is 100-30000. The reattachment lengths for the viscoelastic fluid in the laminar flow region are found to be much shorter than those of the Newtonian fluid, and decrease significantly with the increase of the concentration of viscoelastic fluid is two or three times longer than those of water, and gradually increases with the increase of the concentration of viscoelastic fluid.