• Proceedings of KOSOMES biannual meeting
• /
• 2018.06a
• /
• pp.161-161
• /
• 2018

• Bulletin of the Society of Naval Architects of Korea
• /
• v.27 no.2
• /
• pp.40-46
• /
• 1990

Expressions for the lift and the drag exerted on a circular cylinder by an unsteady flow of an ideal fluid with embedded discrete vortices are derived. The formulae can be used in the discrete vortex method of flow simulation. These formulae are derived via contour integration on the complex plane. Terms have been produced which are significantly different from those in Sarpkaya's formulae. These are expected to bring a change to the forces obtained so far.

• 한국전산유체공학회:학술대회논문집
• /
• 2007.10a
• /
• pp.243-248
• /
• 2007

A three-dimensional (3D) unstructured hydrodynamic solver for transient two-phase flows has been developed. A two-fluid three-field model was adopted for the two-phase flows. The three fields represent a continuous liquid, an entrained liquid, and a vapour field. The hydrodynamic solver is for the 3D component of a nuclear system code and the component-scale analysis tools for transient two-phase flows. The finite volume method and unstructured grid are adopted, which are useful for the flows in a complicated geometry. The semi-implicit ICE (Implicit Continuous-fluid Eulerian) numerical scheme has been adapted to the unstructured non-staggered grid. This paper presents the numerical method and the preliminary results of the calculations. The results show that the numerical scheme is robust and predicts the phase change and the flow transitions due to boiling and flashing problems well.

• 한국전산유체공학회:학술대회논문집
• /
• 2004.10a
• /
• pp.127-130
• /
• 2004

In this study, three-dimensional numerical calculations are peformed to simulate the flow and heat transfer in helically coiled tube steam generator employing a commercial CFD (Computational Fluid Dynamics) code. The problem considered herein includes the boiling phase change flow of tube side fluid and the single-phase counter-current flow of shell side hot fluid transferring heat to the tube side flow thru the tube wall. Detailed investigations are performed for both shell-side and tube-side flow fields in terms of density and volume fractions of each phase of fluids as well as for the tube wall heat transfer field in terms of heat transfer coefficients.

• 한국전산유체공학회:학술대회논문집
• /
• 2006.10a
• /
• pp.126-129
• /
• 2006

Many researchers have made an effort to explain flight mechanism of flapping insects. As a result, several unsteady mechanisms about lift generation in insect flight have been proposed. But it has a limits to elucidate insect's forward flight and abrupt thrust, because most of these are about insect's hovering flight. For this reason, the objective of this paper is to simulate "Figure-of-eight motion" of insect's wing during tethered flight for comprehending aerodynamic property in insect's forward flight.

• 한국가시화정보학회:학술대회논문집
• /
• 2004.11a
• /
• pp.80-83
• /
• 2004

This experiment has been carried out to measure the process of droplet formation between water phase fluid$(PVA\;3\%)$ and organic phase fluid(oil), Internal and External flow fields measured by a Dynamic Micro-PIV method Water-in-oil(W/O) droplets successfully generated at a cross junction and Y junction. Internal and external flow fields were measured when the droplet grew up, stretched and separated.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.5
• /
• pp.103-110
• /
• 2000

A two phase compound jet, which mixes pulverized solid particles with the air in the test section, is experimentally analyzed in this study. Two phase flow is jetted 10 degree upward in the primary jet, while the secondary jet utilizes the air only. The height difference between the primary and secondary central axises is 32.5mm. The velocity vector field, concentration field, and turbulent properties of solid particles are measured by using 3-Dimensional Particles Dynamics Analyzer. When the jet angle of the secondary jet goes into effect, the solid particle recirculation zone becomes larger. Also, solid particle concentration becomes more dense due to a velocity decrement of particles.

• Journal of the Korean Society of Visualization
• /
• v.4 no.2
• /
• pp.81-87
• /
• 2006

In this paper, we present flow patterns around and performance of an air-flow separator by using the numerical analysis. With this separator, particles of different density are to be separated by using the drag force from the air flow. The low-density particles are designed to be separated by using inhalation through holes on a rotating drum. To obtain the flow informations needed for determining the proper design parameters, we have performed numerical simulations by using a commercial code, ANSYS CFX. Various parameter set was tested and it was found that depending on the design of drums there exist critical parameter set regarding the attachment of light particles on the drum, which is prerequisite for the separation of materials. We present here the possibility of using the present design in separation of particles mixed in the clod for use in recycling.

• Computational Structural Engineering
• /
• v.7 no.2
• /
• pp.4-10
• /
• 1994

컴퓨터 성능과 전산유체역학 분야는 지속적으로 발전하고 있으므로 이에 따라 유체의 유동장은 더욱 정확하고 상세히 묘사할 수 있게 될 것이며, 더불어 ALE유한요소법 등과 같은 유체-구조 상호작용해석 기법이 발전해 나갈 것이다. 따라서, 현재 수행되고 있는 풍동실험은 다양한 모형제작으로 인한 비용문제와 완성된 모형의 정밀도 문제, 각 모형에 대한 반복적인 실험과정 등 적절한 설계형상을 선택하는 과정에서 효율성이 낮은 경우가 많으므로 수치해석에 의한 내풍안정성 평가과정을 병행함으로써 실험의 효율성이 낮은 부분을 보완, 최소화할 수 있을 것이다. 특히 적은 비용 및 시간내에 개략적인 내풍안정성 파악이 요구되는 개념설계 및 초기설계단계에 근사적인 내풍안정성 검토 기술로서 결과적으로 활용될 수 있을 것이다. 또한 수치해석기법의 가장 큰 장애요인었던 유체 유동장의 모사정도가 향상됨에 따라 수치해석에 의한 장대구조물의 내풍안정성해석은 앞으로 상당한 발전이 있을 것으로 전망된다.

• Journal of Veterinary Clinics
• /
• v.17 no.2
• /
• pp.450-453
• /
• 2000

식후 만성적인 구토 증상을 보이는 3개월령 암컷 Schunauzer가 본 (주)해마루 소동물 임상 의학 연구소에 내원하였다. 신체 검사시 비정상직인 소견은 보이지 않았으나, 유동식을 공급하는 중에도 식 후 1시간 이내에 포말성 역류 증상을 보였고, 기립 자세에서 식이를 공급 해도 증상은 호전되지 않았다 일반 방사선 검사에서 전반적인 식도 확장이 관찰되었고. 식도 조영술을 실시하여 심기저부 앞부분의 협착과 협착부 전후의 식도 확장을 확인하고 우대동백궁 잔존증으로 진단하였다. 수술을 통해 식도를 압박하고 있는 인대를 제기하고 유동식을 공급하였다. 술 후 임상 증상은 다소 호전이 되었으나 여전히 고형식은 섭취하지 못하고 방사선 검사상 소견도 술전과 큰 차이를 보이지 않았다