• 대한조선학회 특별논문집
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• 대한조선학회 2013년도 특별논문집
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• pp.85-89
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• 2013

In the engine room and the aft body, there are so many fluid tanks such as fresh water tank and oil tank. The vibration analysis for the fluid tank structures has to consider the added mass effect due to the fluid. However, it is known that the result of the fluid tank has the difference according to the boundary condition of the fluid field such as infinite fluid and finite fluid. In this paper, a numerical case study is carried out for the research about the vibration characteristics of the fluid tank with various fluid field. In addition, an experimental study is carried out to verify the validity of the vibration analysis for the fluid tank structure.

• 한국전산유체공학회지
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• 제10권3호
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• pp.36-42
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• 2005

The present study numerically investigates the natural convection heat transfer in a 2-D square cavity containing a centered heat conducting body. Special emphasis is given to the influences of the Rayleigh number, the dimensionless conducting body size, and the ratio of the thermal diffusivity of the body to that of the fluid on the natural convection heat transfer in overall concerned region. The analysis reveals that the fluid flow and heat transfer processes are governed by all of them. Results for isotherms, vector plots and wall Nusselt numbers are reported for Pr = 0.71 and relatively wide ranges of the other parameters. Heat transfer across the cavity, in comparison to that in the absence of a body, are enhanced (reduced) in general by a body with a thermal diffusivity ratio less (greater) than unity. It is also found that the heat transfer attains a minimum as the body size is increased with a thermal diffusivity ratio greater than unity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.833-834
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• 2010

• 센서학회지
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• 제26권3호
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• pp.160-167
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• 2017

Many stroke patients undergoing rehabilitation therapy require a quantitative indicator for the evaluation of body composition in paretic and non-paretic regions. In this study, the body fluid alteration in the paretic and non-paretic regions of stroke patients with hemiplegia caused by cerebral hemorrhage and cerebral infarction was analyzed using bioelectrical impedance analysis (BIA). Alterations in body fluids were investigated to assess the physical status of the paretic and non-paretic regions of 20 stroke patients with hemiplegia caused by cerebral hemorrhage (7 patients) and cerebral infarction (13 patients). Extracellular water (ECW), intracellular water (ICW), ICW/ECW, total body water (TBW), ECW/TBW, and TBW/fat-free mass were utilized to evaluate the functional status of the paretic and non-paretic regions. Compared with the non-paretic region, the paretic region had high ECW and low ICW. Due to the loss of motor function and nutritional imbalance caused by the stroke, the amount of fat increased while the muscle quantity and quality significantly decreased in the paretic region. Thus, BIA can be a useful tool for quantitatively assessing paretic and non-paretic regions in stroke patients with hemiplegia.

• 대한화장품학회지
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• 제40권2호
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• pp.195-201
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• 2014

생체수는 링거액, 인공관절액, 세포 배양 등 다양한 분야에서 연구되어 왔다. 이는 생체수가 체온을 조절하는데 결정적인 역할을 하고, 생체 내 다양한 대사 과정에서 용매로 사용되며, 삼투압이나 능동적 섭취를 통한 혈액 또는 림프액을 통해 세포에서 세포로 전달되는 미네랄, 에너지원, 호르몬, 시그널과 약물의 전달 물질로 이용되기 때문이다. 세포외 지질과 자연보습성분(natural moisturizing factor, NMF)을 함유하는 각질층은 외부의 수분을 끌어들여 내부 수화에 이용하며, 이러한 과정들은 피부 장벽 기능과의 연관성이 높다. 본 연구에서는 피부 장벽 기능을 강화하는 아미노산, 펩타이드, 단당류를 포함한 생체모사수(Cell Bio Fluid SyncTM)를 인체 피부에 처리하여 세포활성을 관찰하고, 생체 모사수를 함유한 제품을 피부에 도포하여 인체피부 개선 효과를 연구 하였다. 피부 세포 활성을 보기 위해 각질세포인 HaCaT 세포를 이용하였고, 에너지 고갈상태로 만들기 위해 3시간 동안 PBS에 전 처리한 후 이후 세포 배양액인 DMEM 및 등장액인 PBS, 생체 모사수(Cell Bio Fluid $Sync^{TM}$)에 각각 3시간 처리하였다. 이후 MTT assay와 이미지 분석을 수행하였다. 인체의 피부 개선 효능을 위한 임상 연구에 21명의 여성이 참여하였다. 생체 모사수를 함유한 제품을 1주일간 안면에 도포하였고, 수분량, 피부결, 밝기 그리고 피부 균일도를 측정하였다. 모든 측정은 피험자가 세안 후 항온항습조건($22{\pm}2^{\circ}C$, $50{\pm}5%$)에서 20분 간 대기하고 수행하였다. 모든 데이터는 SPSS ver. 21을 이용하여 분석하였다. 그 결과, 생체 모사수(Cell Bio Fluid $Sync^{TM}$)가 세포 활성을 높이고 인체의 피부에서 수분, 거칠기, 밝기, 균일도, 투명도 등의 개선 효과가 있음을 확인할 수 있었다.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.57-65
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• 2016

By high speed Liquid Droplet Impingement (LDI) on material, fluid systems are seriously damaged, therefore, it is important for the solution of the erosion problem of fluid systems to consider the effect of material in LDI. In this study, by using an in-house fluid/material two-way coupled method which considers reflection and transmission of pressure, stress and velocity on the fluid/material interface, high-speed LDI on wet/dry material surface is simulated. As a result, in the case of LDI on wet surface, maximum equivalent stress are less than those of dry surface due to damping effect of liquid film. Empirical formula of the damping effect function is formulated with the fluid factors of LDI, which are impingement velocity, droplet diameter and thickness of liquid film on material surface.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.164-165
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• 2003

The problem of a bluff body oscillating in a fluid flow has been receiving a great deal of attention. When a bluff body is placed in a flow, it experiences fluctuating hydraulic forces in both transverse and stream-wise directions. It is caused by the formation of vortices behind the body, which could cause large damages of structures. It is called the flow-induced vibrations. In this article, it is investigated the effects of that side-jets and rear-jet, which is applied to control the vortex shedding. The rear-jet is available to control the flow-induced vibrations according as the body shapes and the velocity of fluid flow in which the galloping phenomena is not appeared.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.78-83
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• 2009

In this study, computer applied engineering (CAE) techniques are fully used to conduct structural and dynamic analyses of a whole huge wind turbine system including composite blades, tower and nacelle. For this study, computational fluid dynamics (CFD) is used to predict aerodynamic loads of the rotating wind-turbine blade model. Multi-body dynamic structural analyses are conducted based on the non-linear finite element method (FEM) by using super-element method for composite laminates blade. Three-dimensional finite element model of a wind turbine system is constructed including power train(main shaft, gear box, coupling, generator), bedplate and tower. The results for multi-body dynamic simulations on the wind turbine's critical operating conditions are presented in detail.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권2호
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• pp.75-86
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• 2010

In this work the possibility of obtaining a rectilinear motion of bodies partially or totally submerged without using propellers is evaluated. The system propulsion is based on a pair of counter rotating masses that generate the thrust. The fluid-body system has been schematized in order to carry out a very simple model. Using this model an evaluation of the body motion along a longitudinal direction was performed. The motion equations of the system were written and integrated. The external forces applied to the body depend on its velocity in relation to the water. These forces were obtained by fluid dynamic simulations. Regarding the mechanical configuration suggested, the results obtained show that a certain displacement of the body along a fixed direction is obtainable.

• Journal of Ship and Ocean Technology
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• 제3권1호
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• pp.1-11
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• 1999

Numerical simulation for the axisymmetric body with contractive and dilative periodic motion is carried out. The present analysis shows that a propulsive force can be obtained in highly viscous fluid by the contractive and dilative motion of axisymmetric body. An axisymmetric code is developed with unstructured grid system for the simulation of complicated motion and geometry. It is validated by comparing with the results of Stokes approximation with the problem of uniform flow past a sphere in low Reynolds number($R_n$ = 1). The validated code is applied to the simulation of contractive and dilative periodic motion of body whose results are quantitatively compared with the two dimensional case. The simulation is extended to the analysis of waving surface with projecting part for finding out the difference of hydrodynamics performance according to variation of waving surface configuration. The present study will be the basic research for the development of the propulsor of an axisymmetric micro-hydro-machine.