• 수산해양기술연구
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• 제28권2호
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• pp.228-239
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• 1992

The purpose of the present research is to develop an efficient numerical method for the calculation of potential flow and predict the wave-making resistance for the application to ship design of tuna purse seiner. The paper deals with the numerical calculation of potential flow around the series 60 with forward velocity by the new slender ship theory. This new slender ship theory is based on the asymptotic expression of the Kelvin-source, distributed over the small matrix at each transverse section so as to satisfy the approximate hull boundary condition due to the assumption of slender body. Some numerical results for series 60, C sub(b) =0.6, hull are presented in this paper. The wave pattern and wave resistance are computed at two Froude numbers, 0.267 and 0.304. These results are better than those of Michell's thin ship theory in comparison with measured results. However, it costs much time to compute not only wave resistance but also wave pattern over some range of Froude numbers. More improvements are strongly desired in the numerical procedure.

• 한국항해항만학회지
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• 제36권10호
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• pp.787-793
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• 2012

최적화기법과 선형변환 자동화기법을 도입하여 고속 중형 Ro-Pax선박의 조파저항성능을 향상시킬 수 있는 선형설계방법에 대하여 연구하였다. 최적화기법으로는 SQP(sequential quadratic programming)을 적용하였으며, 선형변환 자동화기법으로는 NURBS(Non-Uniform Rational B-Spline)기법을 적용하였다. 목적함수인 선박의 조파저항성능을 예측하기 위하여 비선형 자유수면 경계조건과 선체의 침하량을 고려한 비점성 유동 해석 기법인 패널법을 적용하였다. 기준선형에 대하여 선형최적화를 수행하였으며 그 결과로 도출된 최적선형에 대하여 모형선을 제작하여 모형시험을 수행하였다. 기준선형과 최적선형에 대한 수치해석을 수행하여 얻은 결과와 최적선형에 대한 모형시험을 수행하여 얻은 결과를 서로 비교하였다.

• 대한조선학회지
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• 제8권2호
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• pp.45-52
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• 1971

The object of this study is to determine theoretical ship form which minimises wave making resistance under given conditions and developes theoretical ship form planing. By employing the streamline tracing method 1967's Korean Standard Ship Form of 10,000 G.T. linear has been reformed and tested at towing tank of Inha Institute of Technology. The design process and the reformed ship forms had been reported already in reference[4]. In this paper, resistance performance is experimentally observed with three models(original, theoretical, and reformed form) of 2m long in the towing tank, and total resistance of theoretical and reformed ship forms are decreased by 24.9% and 19.7% and wave making resistance by 66.4% and 47.7% compare to original ship form respectively.

• 수산해양기술연구
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• 제35권3호
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• pp.335-342
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• 1999

The purpose of present research is to develop and efficient numerical method for the calculation of potential flow and predict the wave-making resistance for the application to ship design of tuna purse seiner. Havelock was considered the wave resistance of a post extending vertically downwards through the water from the surface, its section by a horizontal plane being the same at all depths and having its breadth small compared with its length. This enables us to elucidate certain points of interest in ship resistance. However, the ship has not infinite draft. So, the problem which is investigated ind detail in this paper is the wave resistance of a mathematical quadratic model in a uniform stream. The paper deals with the numerical calculation of potential flow around the series 60 with forward velocity by the new slender ship theory. This new slender ship theory is based on the asymptotic expression of the Kelvin-source, distributed over the small matrix at each transverse section so as to satisfy the approximate hull boundary condition due to the assumption of slender body. The numerical results using the panel shift method and finite difference method are compared with the experimental results for wigley mono hull. There are no differences in the wave resistance. However, it costs much time to compute not only wave resistance but also wave pattern over some range of Froude numbers. More improvements are strongly desired in the numerical procedure.

• 한국항해항만학회지
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• 제48권4호
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• pp.249-260
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• 2024

본 논문에서는 컨테이너선의 조파 저항을 효율적으로 감소시킬 수 있는 기술과 관련하여 연구한 내용을 정리하였다. 컨테이너선에 적용이 가능한 조파저항 저감 기술을 개발하고 실선 설계에 사용하기 위하여 최적화 알고리즘, 선체 형상 변경 알고리즘, 선박 성능 예측 알고리즘, 자동화 알고리즘 그리고 반복적 최적 설계 기법을 적용하여 선형 최적 설계를 수행할 수 있는 컴퓨터 프로그램을 개발하였다. 선형최적 설계에 있어서 중요한 요소인 설계 변수의 적절한 설정과 설계 변수의 하한과 상한을 효율적인 설정을 위하여 민감도 분석 알고리즘을 개발하여 선형 최적 설계에 적용하였다. 개발된 컴퓨터 프로그램의 신뢰성과 실선 적용성을 예측하기 위하여 전 세계적으로 다양한 연구가 진행된 컨테이너선인 KCS(KRISO Container Ship) 선박에 대한 선형 최적 설계를 수행하였다. KCS 선박의 설계 속도인 Fn=0.26에서 선형 최적 설계를 수행하였으며, 대상 선박인 KCS 선박의 선형과 선형 최적 설계의 결과로써 도출된 선박의 선형에 대한 수치해석을 수행하여 조파 저항, 파형 그리고 파고를 구하고 서로 비교하였다. 결론적으로, 최적 선박은 대상 선박과 비교하여 조파 저항이 80.60% 감소하였고, 배수량과 침수 표면적은 각각 1.54%, 1.21% 감소하는 것을 알 수 있었다.

• 대한조선학회논문집
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• 제48권2호
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• pp.99-106
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• 2011

The appearance of CSR changes the concept of the hull form design as well as structural design, since the application of CSR inevitably brings the lightweight increase of a ship. Keeping the original design constraints such as principal particulars, deadweight, and speed performance, designers have to increase the volume of the hull form. As a result, the entrance angle at bow end should become larger, which results in blunter waterline shape. For a slow and full ship having high $C_B$ more than 0.85, a new concept of bow shape has been required to alleviate the increase of wave-making resistance, since it is very difficult to improve waterline and frameline shape for such a full ship. In this paper a new bow shape of Capesize Bulk Carrier was developed to improve its wave-making characteristics without incompliance with the design constraints. For loading manual calculation, NAPA software was used. FLUENT6.3.26 and WAVIS1.4 were used to evaluate resistance performance of the subject hull forms. The newly designed hull form was tested at SSPA model basin for the final confirmation of resistance and propulsion performance of the ship. It was found that the new bow shape of a Capesize Bulk Carrier improved the resistance characteristics greatly compared to a conventional bulbous bow. The other benefits of new bow shape on the manufacturability were also investigated.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.251-253
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• 2003

This paper discusses some practical problems of the determination of ship wave resistance from flow calculation and the model test. there are so many kind of CFD program as FLUENT, WAVIS, SHIPFLOW, COMET etc. for finding optimized hull. we should know how much percent we trust the program. so if we gather computed values of the wave resistance we'll able to get more accurated values of presumptive.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권5호
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• pp.785-794
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• 2015

To obtain low resistance and high efficiency energy-saving ship, minimum total resistance hull form design method is studied based on potential flow theory of wave-making resistance and considering the effects of tail viscous separation. With the sum of wave resistance and viscous resistance as objective functions and the parameters of B-Spline function as design variables, mathematical models are built using Nonlinear Programming Method (NLP) ensuring the basic limit of displacement and considering rear viscous separation. We develop ship lines optimization procedures with intellectual property rights. Series60 is used as parent ship in optimization design to obtain improved ship (Series60-1) theoretically. Then drag tests for the improved ship (Series60-1) is made to get the actual minimum total resistance hull form.

• 대한조선학회지
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• 제7권2호
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• pp.41-60
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• 1970

Despite it's limitations, the existing Stream Line Tracing Method(Inverse Method) can be applied effectively to the design of better hull forms with practical proportions. Most of the calculating mechanism by the method for hull form design has been achieved. In this paper, authors have tried to improve the quality of wave making resistance on the 10,000GT liner among FY'67 Korean Standard Ship Form. Some numerical results obtained in this work and designed new lines are shown.

• 대한조선학회지
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• 제24권2호
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• pp.55-61
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• 1987

The wave system due to a moving submerged body is investigated both theoretically and numerically. Boussinesq equation, which is derived under the assumption that the effects of nonlinearity and wave dispersion are of the same order, is generalized to take the forcing agency into account. Furthermore, under the more restrive assumption that the disturbance is of higher order, inhomogeneous Korteweg-de Vries equation is derived. These equations are solved numerically to obtain the generated wave system and the wave-making resistance. These results are compared with those given by the linear theory.