CIP 법을 이용한 동적 접촉각을 고려한 벽면 충돌 후 액적의 퍼짐 현상에 대한 수치해석 연구

손소연(So Youn Son),고권현(Gwon Hyun Ko),명상엽(Sang Yeong Myeong),박정렬(Jeung Yeul Park),최영환(Yeong Hwan Choi),유홍선(Hong Sun Ryou) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

Droplet impinging phenomena frequently happens in many fields such as spray cooling, coating and inkjet technology and it became origin of single droplets impingement and spray process to modify. Droplet behavior after collision is relative to droplet velocity, droplet size and other parameters. Simulation of contact angle between wall and droplet in wetting phenomena, in particular, accounts for inertia force, viscous force, gravity and surface tension. While static contact angle which is material property has influent to analyze phase interaction between gas and liquid phases, dynamic contact angle is necessary to calculate for dynamic interaction. Dynamic contact angle has various values according to capillary numbers in term of droplet velocity, viscous force and surface tension. The aim of this study is that numerical result considering dynamic contact angle is compared with the numerical data when using static contact angle and experimental data. The numerical result predicted well the deformation of droplet spreading radius and height. The numerical results considering dynamic contact angle have smaller spreading radius and higher height than the data considering static contact angle. Furthermore, the numerical result shows good agreement with experimental data in spreading diameter, height and contact angle change as time elapsed.

수정된 CIP방법을 이용한 벽면 충돌 후 액적의 퍼짐 현상에 대한 수치해석 연구

손소연(S.Y. Son),고권현(G.H. Ko),이성혁(S.H. LEE),유홍선(H.S. Ryou) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5

Interface tracking of two phase is significant to analyze multi-phase phenomena. The VOF(Volume of Fluid) and level set are well known interface tracking method. However, they have limitations to solve compressible flow and incompressible flow at the same time. CIP(Cubic Interpolate Propagation) method is appropriate for considering compressible and incompressible flow at once by solving the governing equation which is divided up into advection and non-advection term. In this article, we analyze the droplet impingement according to various We number using improved CIP method which treats nonlinear term once more comparison with original CIP method. Furthermore, we compare spread radius after droplet impingement on the wall with the experimental data and original CIP method. The result using improved CIP method shows the better result of the experiments, comparison with result of original CIP method, and it reduces the mass conservation error which is generated in the numerical analysis comparison with original CIP method.

성소수자의 커뮤니티 참여 의미에 대한 연구

손소연(Son, So Yeon),이지하(Lee, Jie Ha) 한국사회복지학회 2016 한국사회복지학 Vol.68 No.2

본 연구는 성소수자들을 대상으로 성소수자 커뮤니티 참여경험을 통한 의미본질을 탐색하고자 하는 목적에서 성소수자 커뮤니티에 진입하고자 하는 이유와 커뮤니티 활동경험을 통해 나타나는 본질적 의 미구조에 대해 살펴보고자 했다. 본 연구의 참여자는 성소수자 8명이었으며 자료 수집은 심층 면접을 통해 이루어졌다. 연구자료는 Giorgi의 현상학적 방법론을 바탕으로 분석되었다. 연구 결과 성소수자 들의 참여는 13개의 의미단위와 6개의 도출된 주제, 3개의 본질적 주제로 나타났으며, 그 주제는 ‘채 워지지 않는 목마름’, ‘오아시스라는 또 다른 세계’, ‘나는 진정한 이반!’으로 나타났다. 그리고 본질적 주제를 바탕으로 연구 참여자들의 공통된 본질의 의미는 ‘영혼의 디아스포라’ 로 도출되었다. 본 연구 를 바탕으로 성소수자 커뮤니티의 발전 방향을 다음과 같이 모색해 볼 수 있다. 첫째, 성소수자 커뮤 니티간의 상호 교류를 활성화함으로써 상호보완을 통해 커뮤니티 발전에 기여해야 할 것이다. 둘째, 커뮤니티 활동에 있어서 보다 다양한 사람들이 참여하고 그 욕구가 반영될 수 있도록 성소수자 중에 서도 다양성을 고려되어야 할 것이다. 셋째, 사회복지 현장에서 성소수자 커뮤니티가 소외된 집단으로 머물러 있지 않도록 성소수자 커뮤니티에 대한 올바른 지식 바탕으로 한 관심과 지원 및 교류가 필요 할 것이다. This study aims to illustrate the essence of meaning through sexual minorities’ participant experiences in a sexual minority community. This research intends to explore essential meaning structure revealed in sexual minorities’ reasons for joining a sexual minority community and in their experience in community activities. The study participants were 8 sexual minorities, and data was collected by in-depth interview. Data analysis was described using Giorgi’s analysis methodology in phenomenological research method. As a result, the sexual minorities’ participation was consisted of 13 meaning units, 6 derived topics, and 3 essential topics, which were ‘An unquenchable thirst’, ‘Another world called oasis’, and ‘Real estrangement’ Moreover, based on the essential topics, the study participants’ common meaning of essence was analyzed as ‘spiritual diaspora’. Sexual minority communities shall contribute to developments of own organizations through mutual compensations by vitalizing exchanges with other communities based on this study. Also, the communities should the variety in sexual minorities to allow various people’s participation. People’s awareness on sexual minorities must be transformed so that closed communities can change. Comprehensive knowledge on sexual minorities should be distributed in the social welfare fields so that sexual minorities may search solutions on issues through various access not limited to certain communities.

열전달을 수반하는 액적의 퍼짐 현상에 대한 수치해석 연구

손소연(S.Y. SON),고권현(G.H. KO),유홍선(H.S. RYOU) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5

Contact angle is significant parameter to simulate droplet spreading after impingement on the wall because it is based on analysis of surface tension that is important term in the momentum equation. In almost numerical approaches, it is implemented in the boundary condition as constant value. However, contact angle has various values as different time and contact line velocities. In this paper, the simulation of droplet spreading on the heated surface is presented and both static contact angle and dynamic contact angle which is function of contact line velocities and time are considered as boundary condition to calculate surface tension. Newly modeled function which is obtained the experiment of single droplet spreading and impingement on the flat bare wall is used for dynamic contact angle. The VOF (Volume of Fluid) method which is one of the most famous interface tracking methods and CSF (Continuum Surface Force) model are used for calculation of interface between two phases. Overall, in the numerical result of droplet spreading and impingement on the heated surface, the heat exchange (flux) is affected by contact angles. Furthermore, this heat exchange affects the dynamics of droplet. The larger Weber number shows larger heat exchange between droplet and surface, larger droplet spreading radius and lower spreading height.

포스터 전시회 : 웨버수에 따른 동적 접촉각 고려 시 액적 충돌 및 퍼짐 현상에 대한 수치해석적 연구

손소연 ( So Youn Son ),김소윤 ( So Yoon Kim ),고권현 ( Gwon Hyun Ko ),유홍선 ( Hong Sun Ryou ) 한국액체미립화학회 2012 한국액체미립화학회 학술강연회 논문집 Vol.2012 No.-

The contact angle is one of the significant parameters to simulate droplet spreading phenomena after impingement on the solid surface. It is usually assumed that contact angle is a material property and adapted in boundary condition to analyze the droplet spreading motion. However, in wetting phenomena, contact angle has various values according to contact line movement. In the present study, we analyze the droplet spreading and impingement motion considering dynamic contact angle function that is obtained from single droplet impingement and spreading experiment on the bare and flat surface for different Weber numbers. Fluent 6.3 is used for droplet simulation and Volume of Fluid (VOF), the most famous interface tracking method, is adapted for analysis of interface between liquid and gas phases. The numerical result considering dynamic contact angle is compared to the experimental data, numerical result using the Cubic Interpolated Pseudo-particle (CIP) method by Yabe, and numerical result considering static contact angle in terms of droplet deformation, spreading radius, spreading height at Weber numbers, 4.43 and 11.33, respectively. The study shows that numerical results agree well with the experimental data in maximum spreading radius and spreading height. Indeed, overall, the study shows increasing spreading radius and height as the Weber numbers increase.

유산양에서 관절염,뇌염 발생

손소연 ( So Yeon Son ),류대열 ( Hyeon Soo Son ),손현수 ( Dae Yeol Ryu ),강신석 ( Sin Seok Kang ),박재명 ( Jae Myoung Park ),변현섭 ( Hyeon Seop Byeon ),최해연 ( Hae Yeon Choi ) 한국가축위생학회 2006 韓國家畜衛生學會誌 Vol.29 No.3

This is a case report on the occurrence of caprine arthritis-encephalitis(CAE) disease among dairy goats in a local farm located in Yeongdong-gun, Chungbuk. Previously, it was reported that the farm experienced intermittent deaths numbering 15 of the 97 goats raised for 5 months. Most of the goats less than 6 months of age were suffering from ataxia and posterior paresis, body tremor and abnormal head posterior. Affected animals frequently had stunted growth and had a rough coat. Goats more than 6 months of age were affected with an insidious, chronic arthritis characterized by articular swelling("big knee") of the carpal, hock, and stifle joints. Necropsy revealed severely swollen mesenteric lymph nodes, under-flow of 2-3㎖ synovial fluid in the articular space and fibrous proliferation of synovial membrane. Histopathological examination showed perivascular accumulations of mononuclear inflammatory cells in the white matter of the brain, proliferative synovitis characterized by villous hypertrophy, synovial cell hyperplasia and infiltration by mononuclear inflammatory cells. Pulmonary lesions consists of patchy interstitial pneumonia with hyperplasia of lymphoid tissues and an extensive mononuclear inflammatory cell infiltration into the alveolar septa. Confirmation by nested PCR involves amplification of a 296bp(1st PCR) and 184bp(2nd PCR) fragments corresponding to the gag region of the CAE virus. This is the first time CAE has been reported in a local farm in Korea and emphasizes the importances of developing preventive measures against CAE.

수정된 CIP 방법을 이용한 벽면 충돌 후 액적의 퍼짐 현상에 대한 수치해석 연구

손소연(S.Y. Son),고권현(G.H. Ko),이성혁(S.H. Lee),유홍선(H.S. Ryou) 한국전산유체공학회 2010 한국전산유체공학회지 Vol.15 No.4

Interface tracking of two phase is significant to analyze multi-phase phenomena. The VOF(Volume of Fluid) and level set are well known interface tracking method. However, they have limitations to solve compressible flow and incompressible flow at the same time. ClP(Cubic Interpolate Propagation) method is appropriate for considering compressible and incompressible flow at once by solving the governing equation which is divided up into advection and non-advection term. In this article, we analyze the droplet impingement according to various We number using improved ClP method which treats nonlinear term once more comparison with original ClP method. Furthermore, we compare spread radius after droplet impingement on the wall with the experimental data and original ClP method. The result using improved ClP method shows the better result of the experiments, comparison with result of original ClP method, and it reduces the mass conservation error which is generated in the numerical analysis comparison with original ClP method.

고온 벽면에 충돌하는 분무 액적의 액막형성 및 열전달에 대한 수치해석 연구

고권현(Gwon Hyun Ko),손소연(So Yeon Son),노경철(Kyoung Chul Ro),유홍선(Hong Sun Ryou) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11

The main purposes of this article are modeling the heat transfer process of liquid film produced by spraying droplets and analyzing the characteristics of impinging sprays on the hot surface. The Eulerian-Lagrangian approach is used for the interaction between gas phase and sprays with several sub-models. A new model is proposed for the liquid film formation and its heat transfer, and it is coupled with our previous model for spray/wall interaction. The new model is derived from mass, momentum, and energy conservation considering the liquid film formation by impinging droplets and spreading by successive addition of impinging droplets with the heat transfer to surrounding gas phase and wall surface. To assess the new model, numerical results using the new model are compared with experimental data. The liquid film dynamics and heat transfer by impinging fuel spray on heated wall are analyzed and the limitations of the present model are discussed.