• Bulletin of the Society of Naval Architects of Korea
• /
• v.32 no.1
• /
• pp.21-27
• /
• 1995

초고속선에 관련된 점성유동은 저한성능 향상과 운항자세 제어를 위해 사용되는 다양한 선체부 가물의 저항 예측과 초고속선에 많이 사용되는 물분사 추진장치 입구 형상의 설계 그리고 임펠 러에 이르는 덕트 유동의 예측을 중심으로 관심을 받아왔다. 본 소고에서는 통상적인 선박의 경우와는 구별되는 초고속선 고유의 점성유동 특성에 관하여 간략히 논의하기로 하고 내용을 크게 선체-부가물 점성유동과 물분사 추진장치에 관련되어 있는 덕트유동으로 나누어 기술하 였다.

• Industry Promotion Research
• /
• v.6 no.1
• /
• pp.33-42
• /
• 2021

Human beings have to do economic activities according to their aptitude and innate ability for a living. Human beings invest a lot of effort and spend a lot of time to gain social status and honor via economic activities. In order to make their lives more valuable as members of society, first they should know their own nature. Because it is important for choosing a job. From a study on the use of personality psychology of classical astrology, it was found that the native shows disposition and personality psychology differently depending on the change of yin and yang. Since human behavior is determined by natural personality and the influence of the surrounding environment, knowing personality makes people expect job choices and changes. Therefore, it is expected that it will be helpful to classify native's occupational aptitude of personality type from research on the use of personality psychology of classical astrology.

• Industry Promotion Research
• /
• v.8 no.4
• /
• pp.221-227
• /
• 2023

This study is a study to analyze Nativity's occupational aptitude by examining the functions and structures of the planets that make up the Nativity birth chart of Classic Astrology. If the occupation that appears in the birth chart is viewed as an individual's natural occupation, it is analyzed through the strength and weakness of the sign and planets, and the aspect (relationship with the planet). In Classic Astrology's nativity birth chart, there are three major planets when judging occupations: Venus (♀). Mars (♂). It was thought to be determined by Mercury (☿). However, in order to meet the diversity of jobs required in today's highly developed knowledge and information society, there are some shortcomings, so Saturn (♄), Jupiter (♃), Sun (☉), Moon (☽) was added to apply the aptitude for the job. Thus, the native's ASC vocational aptitude could be applied more diversely and broadly based on the relationship between planets and their aspects. As a result, Venus (♀. Venus) means enjoying artistic work that people think is beautiful and making it a pleasure in life, while Mars (♂) means work that requires physical strength and strength, such as working days. Mercury (☿) means using knowledge and brains, and the Sun (☉) plays a role in giving authority to jobs and talents. The Moon (☽) helps the native gain people's trust in his or her profession and talents, Jupiter (♃) helps the native to revive his or her profession and talents through faith, sincerity, fairness, and generosity, and Saturn (♄) can appear as an obstacle that blocks career and talent due to greed, sadness, poverty, etc. As a result of the study, it was found that the native's occupations vary depending on the strengths and weaknesses of the planets and their aspect relationships.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.1
• /
• pp.132-141
• /
• 1992

The critical condition for onset of Benard convection with variable viscosity .nu.=.nu.$_{0}$exp(-CT) has been obtained using a linear stability theory. The bottom wall is rigid while the upper surface may be either free or rigid. The two boundaries are subject to convective heat transfer. The critical Rayleigh numbers are presented up to maximum viscosity ratio of 3000. It is greater for smaller upper and/or lower surface Biot numbers. Its dependence on the viscosity ratio is complicated. However, a simple sublayer theory is found to be applicable for extremely large viscosity ratio. In such cases, the critical Rayleigh number and the critical wave number are functions of viscosity ratio and lower surface Biot number.r.

• Journal of the Korean Ceramic Society
• /
• v.36 no.3
• /
• pp.266-273
• /
• 1999

본 연구에서는 겔캐스팅법의 제조공정 확립을 위하여 분산제의 분자구조가 질화규소 슬립의 점성특성 및 성형체의 상대밀도와 기계적 특성에 미치는 영향을 조사하였다. 슬립과 겔캐스팅 성형체의 제조방법은 기보고된 방법과 동일하게 하였다. 그 결과, 겔캐스팅 슬립의 점성은 분산제의 분자구조와 모노머와 분산제의 구성비율에 크게 의존하였다. PMAA 분산제를 사용한 슬립의 점성은 PAA 및 PAAm 분산제 보다 높은 점도를 나타내었다. 성형체의 상대밀도는 슬립의 농도에 크게 의존하였으며, 분산제양과 모노머의 양변화에는 그다지 변화가 없었다. 그리고, 겔캐스팅 성형체의 기계적 특성은 크게 모노머의 농도에 의존하였으며, 분산제양과 슬립의 농도에는 큰 변화가 없었다.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.5 no.2
• /
• pp.63-69
• /
• 1968

• Journal of Korean Association for Spatial Structures
• /
• v.21 no.2
• /
• pp.18-25
• /
• 2021

• Journal of Korean Association for Spatial Structures
• /
• v.20 no.3
• /
• pp.15-20
• /
• 2020

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.8
• /
• pp.677-684
• /
• 2007

In the Present Study, a 3-D viscous flow solver, based on unstructured hybrid meshses containing tetrahedra, prisms and pyramids, has been developed. A finite-volume discretization scheme is used for solving the compressible Navier-Stokes equations. A cell-vertex median dual volume is used for spatial discretization. The one-equation Spalart-Allmaras turbulence model has been adopted to evaluate the eddy viscosity. Validation were made by computing laminar and turbulent flows around a 3-D wing for steady flows and turbulent flows around an oscillating 3-D wing in harmonic motion for unsteady flows.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.17 no.1
• /
• pp.25-32
• /
• 2014

Recently supercavitating torpedo has been studied because of its high-speed performance as the next generation of underwater weapon systems. In this study, we present a numerical method based on the potential flow. Characteristic features of the shape of supercavities and drag forces are investigated. In addition, we introduce a viscous-potential method to compensate for the effects of viscosity. The results are compared with viscous calculations using a commercial package, FLUENT V13.