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Newton's Method to Determine Fourier Coefficients and Wave Properties for Deep Water Waves
신장용 한국해양공학회 2023 韓國海洋工學會誌 Vol.37 No.2
Since Chappelear developed a Fourier approximation method, considerable research efforts have been made. On the other hand, Fourier approximations are unsuitable for deep water waves. The purpose of this study is to provide a Fourier approximation suitable even for deep water waves and a numerical method to determine the Fourier coefficients and the wave properties. In addition, the convergence of the solution was tested in terms of its order. This paper presents a velocity potential satisfying the Laplace equation and the bottom boundary condition (BBC) with a truncated Fourier series. Two wave profiles were derived by applying the potential to the kinematic free surface boundary condition (KFSBC) and the dynamic free surface boundary condition (DFSBC). A set of nonlinear equations was represented to determine the Fourier coefficients, which were derived so that the two profiles are identical at specified phases. The set of equations was solved using Newton’s method. This study proved that there is a limit to the series order, i.e., the maximum series order is N=12, and that there is a height limitation of this method which is slightly lower than the Michell theory. The reason why the other Fourier approximations are not suitable for deep water waves is discussed.
액체 화물창내의 SLOSHING 고유주기 산정에 관한 연구
신장용,강신영,최경식,김현수 韓國海洋大學校 附設 海洋科學技術硏究所 1993 硏究論文集 Vol.2 No.1
Recently in the design of super tankers or LNG carriers which transport a large amount of liquid in the cargo holds, the structural damage due to liquid sloshing becomes an important problem. The impact pressure from sloshing is most violent when the liquid motion of a partially filled tank is in resonance with the motion of a ship. In this paper, to avoid the possible structural damages on tank walls the sloshing natural periods in liquid cargo tanks are estimated for partially filled tanks with various geometries. Especially the sloshing periods of baffled tanks which are often installed to reduce liquid motion and sloshing forces, are calculated and the results are compared with numerical results.
신장용(Jang-Ryong Shin),우종식(Jong-Sik Woo) 한국해양공학회 1999 韓國海洋工學會誌 Vol.13 No.4
A deep sea vehicle must be designed to ensure its safety under ultra-high pressure circumstances. If a pressure housing of a deepsea vehicle is collapsed by ultra-high pressure, the deepsea vehicle may be lost.<br/> The objective of this paper is to introduce a design collapse pressure for the deep sea pressure vessel which is composed of one cylinder and two hemispheres. Especially the collapse pressure of hemispherical shell with a hole at top is analyzed by a variational approach (weighted residual method). And for the purpose of design, the safty factor of collapse pressure is presented which is analyzed by interpolation method.
신장용,강신영,최경식 韓國海洋大學校 附設 海洋科學技術硏究所 1994 硏究論文集 Vol.3 No.-
The fluid motion inside a partially filled tank is called "sloshing" and it is of great concern to structural designers of ships. Sloshing analysis is significant, especially in the design of liquid cargo vessels such as LNG carriers and crude oil tankers, since sloshing loads attain such considerable value enough to cause structural damage. In this paper, three dimensional governing equations and exciting forces are derived for the study of sloshing phenomena. In order to include the nonlinearity that occurs at the fluid-tank interface and to avoid the complex boundary conditions on moving walls, a fixed coordinate system to the moving tank is adopted.
화물과 트롤리가 만드는 로프각이 화물의 진자운동에 미치는 영향: 적합조건과 분기조건
신장용(JANG-RYONG SHIN),고성희(SUNG-HEE GOH),홍경태(KYUNG-TAE HONG),홍금식(KEUM-SHIK HONG) 한국해양공학회 2005 韓國海洋工學會誌 Vol.19 No.2
This paper investigates the relationship between the fleet-angle of the hoisting rope and the swaying and pitching angles of a cargo in container cranes. It is found that for a given disturbance, when the fleet-angle is large, the sway Angle becomes smaller, but the pitching angle becomes larger. Therefore, for a quick suppression of a sway motion, it is desirable to have a large fleet-an gle. The compatibility and bifurcation conditions, regarding instability, are characterized.
로프각이 화물의 진자운동에 미치는 영향: 설계력의 계산
신장용(JANG-RYONG SHIN),박영현(YONG-HYUN PARK),고성희(SUNG-HEE GOH),홍금식(KEUM-SHIK HONG) 한국해양공학회 2005 韓國海洋工學會誌 Vol.19 No.1
Over the last 10 years, significant changes have taken place in the world of container shipping. The size and the speed of the quay-side crane have been increased considerably. As a result, the stiffness of a crane is decreased and the sway oscillation of cargo may become violent. The purpose of this paper is to determine the design force caused by the sway oscillation of the cargo, lifted by four ropes, with an initial fleet angle, and the governing equations of the lifting system for an anti-sway control system design.
액체 화물창내의 SLOSHING 고유주기 산정에 관한 연구
신장용(J.R. Shin),최경식(K.S. Choi),강신영(S.Y. Kang),김현수(H.S. Kim) 한국해양공학회 1994 韓國海洋工學會誌 Vol.8 No.2
Recently in the design of super tankers or LNG carriers which transport a large amount of liquid in the cargo holds, the structural damage due to liquid sloshing becomes an important problem. The impact pressure from sloshing is most violent when the liquid motion of a partially filled tank is in resonance with the motion of a ship. In this paper the sloshing natural periods in liquid cargo tanks are estimated for partially filled tanks with various geometries. Especially the sloshing periods of baffled tanks which are often installed to reduce liquid motion and sloshing forces are calculated. A variational method is adopted to analyze the baffled tank of arbitrary filling depth of liquid. In this approach the liquid domain is divided into several subdomains in which the analytic solutions are presented. In consideration of abrupt shape change due to baffles, the kinetic and potential energy are calculated from the velocity potentials in each subdomain. By minimizing the Hamilton's functional, the sloshing natural periods are estimated and the results are compared with experimental and numerical results.
임신 초기 임신양상에 따른 혈청 β-hCG의 결과 예측에 의한 희석배수 참고치 설정
김윤식,신장용,서영미,유신수,Kim, Yoon Sik,Shin, Jang Yong,Seo, Yeong Mi,Yoo, Shin Soo 대한임상검사과학회 2004 대한임상검사과학회지(KJCLS) Vol.36 No.2
This study was carried out to predict the value of serum ${\beta}$ subunit of humans chorionic gonadotropin(${\beta}$- hCG) in early pregnancy viability. This was performed among 85 women in vitro fertilization and embryo transfer(IVF-ET). The serum ${\beta}$-hCG levels were established for 30 normal singleton pregnancies, 10 twin and triplet pregnancies, 10 preclinical abortions, 10 clinical abortions, 20 biochemical abortions and 5 ectopic pregnancies. In comparison to normal singleton pregnancies, multiple pregnancies showed higher ${\beta}$-hCG. But clinical abortions, preclinical abortions and ectopic pregnancies showed lower ${\beta}$-hCG levels than singleton pregnancies. In conclusion, if we predict the value of serum ${\beta}$-hCG of variable early pregnancies and analyze it, we could predict the dilution protocol. Also, it can be useful in other ways.