• 제목/요약/키워드: slender-body approach

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Unified Theory for the Radiation Problem of Multiple Slender Bodies

  • Kim, Yong-Hwan
    • Journal of Ship and Ocean Technology
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    • 제7권2호
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    • pp.1-19
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    • 2003
  • This paper introduces a unified theory for the radiation problem of adjacent multiple floating bodies. The particular case of interest is the multiple slender bodies that their centerlines are parallel. The infinite-and finite-depth unified theories for the single-body problem are extended to solve each sub-problem of multiple bodies. The present method is valid for deep water and moderate water depth, and applicable for individually floating bodies as well as multimaran-type vehicles. For the validation of the present method, the heave and pitch hydrodynamic coefficients for two adjacent ships are compared with the results of a three-dimensional method, and an excellent agreement is shown. The application includes the hydrodynamic coefficients and motion RAOs of four trimarans which have different longitudinal and transverse arrangements for sidehulls.

Cross-flow Analogy and Euler Solutions for Missile Body Aerodynamics

  • Lee, Jae-Myung;Park, Seung-O;Kim, In-Sun
    • International Journal of Aeronautical and Space Sciences
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    • 제1권2호
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    • pp.9-16
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    • 2000
  • For aerodynamic design of missile bodies of non-circular cross-section, the combination of the slender body theory and the cross-flow analogy can hardly be applied owing to the lack of experimental data. An alternative is to utilize the Euler solution in the design stage. For enhanced accuracy, however, an adequate viscous correction is necessary to the Euler solution. In this work, such a procedure is examined to compensate the viscous effect by utilizing the concept of proportionality factor in cross-flow analogy. Predictions of aerodynamic coefficients combining the Euler solution and the viscous correction via proportionality factor are made for a missile body of elliptic cross-section. Results indicate that the present approach can be adopted in designing missile bodies of non-circular cross-sections.

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외모(外貌)에 있어서 가상(假想) 3D 패션 코디네이션에 대(對)한 질적(質的) 연구(硏究) (A Qualitative Study about Coordination system of 3D Virtual Model)

  • 신효정;김효숙;최창석
    • 패션비즈니스
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    • 제7권2호
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    • pp.143-155
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    • 2003
  • The purpose of this study were to investigate 1) Values placed upon born hereditary appearance and a made up appearance, 2)examined for points of body and clothing and 3)discrepancy in opinions about Coordination system of 3D Virtual Model This study chose qualitative research approach in-depth interviews were from December 12, 2002, to February 20, 2003. The subjects of the study were 12 women aged in twenties 12 women aged over forty. The results of this study were as follows. 1. Women aged in their twenties defined appearance as follows. there are important a made up appearance, Appearance is looking at point of view from body shape to face, makeup, hair style, body image, cosmetic surgery, clothing and is looking at the whole point of view from hair to tiptoe. This seems to include attitude, personality, behavior, images, and feeling. 2. Regarding body image Women aged in their twenties prefer a slender figure. Women aged in their twenties exerts all possible efforts to have an attractive body through dress well. 3. Regarding body image Women aged in their twenties prefer coordinate to system of 3D virtual model.

Research on a Sea Snake Robot

  • Shiozaki, Hiroshi;Shimizu, Etsuro;Ito, Masanori
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.951-956
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    • 2005
  • Since a snake achieves various movements just by a slender body, the mechanism of it is very amazing Many researches have been focusing on a snake like robot and have done for it on the ground. However the meander motion of the snake not only can be done by ground creatures, but also can be done by a water creature such as a sea snake or an eel. Therefore, the purpose of our research is to develop an autonomous underwater robot like the sea snake. As an approach to this goal, we develop an experimental sea snake-like-robot for examining basic characteristics, including propulsion, a turning and other performance. Our developed robot is composed of the head and 4 bodies. Each body equips one servomotor, which is operated with pulse signal. In the head unit, 1- chip-microcomputer, which generates the servomotor control signal for realizing a snake motion and the battery, is equipped. Our robot is covered with a rubber film for the waterproof. Using our developed robot, characteristics of the snake-like-robot moved in water are examined.

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인장계류식 해양구조물의 동적응답 특성 (Dynamic Response Characteristics of Tension Leg Platforms in Waves)

  • 이창호;손영길
    • 동력기계공학회지
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    • 제2권2호
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    • pp.81-86
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    • 1998
  • The dynamic response characteristics of Tension Leg Platforms(TLPs) in waves are examined for presenting the basic data for design of TLPs. The numerical approach is based on a combination of the three dimensional source distribution method and the dynamic response analysis method, in which the superstructure of TLP is assumed to be flexible instead of rigid. Restoring forces by hydrostatic pressure on the submerged surface of a TLP have been accurately calculated by excluding the assumption of the slender body theory. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in the motion and structural analysis. Numerical results are compared with the experimental ones, which are obtained in the literature, concerning the motion and tension responses of a TLP in waves. The results of comparison confirmed the validity of the proposed approach.

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종규칙파중(縱規則波中)에서의 선박(船舶)의 부가저항(附加抵抗) 계산(計算) (On the Added Resistance of a Ship in a Regular Head Sea)

  • 김효철
    • 대한조선학회지
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    • 제20권3호
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    • pp.17-20
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    • 1983
  • There have been many investigations of predicting the added resistance of a ship in seaway since Havelock discussed this topic in 1937. Among these researches, Maruo's theoretical approach is known as the most consistent mathematical representation for added resistance of a ship in regular head sea. In his theory, the hull form of a ship is represented under the slender body approximation. But the motion responses which were used for the calculation of the added resistance have been obtained by using the strip method which is based on an approximation that the hull form may be expressed as set of two dimensional cylinder sections in longitudinal direction. Therefore two different methods for hull form representation were implicity used in Maruo's original work for the added resistance calculation. Utilizing the characteristics that hull forms are usually slender, Kan expressed the hull form as two dimensional cylinder at each station by using the Taylor series expansion for the length wise direction. Putting this idea into Maruo's original work, the added resistance can be obtained with the explicitly unique representation of the hull form. For the purpose of comparison the added resistance of a hull form(series 60, Cb=0.6) was calculated by using the motion response obtained by Shintani. The numerical result showes a good qualitative agreement with the experimental result by Sibul.

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인장계류식 해양구조물의 동적응답해석(II) (A dynamic response Analysis of Tension Leg Platforms in Waves (II))

  • 구자삼;박찬후;이창호
    • 한국해양공학회지
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    • 제10권1호
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    • pp.25-35
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    • 1996
  • A numerical procedure is described for predicting the motion and structural responses of tension leg platforms(TLPs) in waves. The developed numerical approach is based on a combination of a three dimensional source distribution method and the dynamic response analysis method, in which the superstructure of TLPs is assumed to be flexible instead of rigid. Restoring forces by hydrostatic pressure on the submerged surface of a TLP have been accurately calculated by excluding the assumption of the slender body theory. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in the motion and structural analysis. The equations of motion of a whole structure are formulated using element-fixed coordinate systems which have the orgin at the nodes of the each hull element and move parallel to a space-fixed coordinate system. Numerical results are compared with the experimental and numerical ones, which are obtained in the literature, concerning the motion and structural responses of a TLP in waves. The results of comparison confirmed the validity of the proposed approach.

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p-Version 적층모델을 통한 팻취 보강된 강판의 선형탄성파괴역학 해석 (LEFM Analysis of Patch Repaired Steel Plates by p-Version Layer Model)

  • 한상현;신영식;우광성
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2007년도 정기 학술대회 논문집
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    • pp.487-492
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    • 2007
  • The enhancement of the service life of damaged or cracked structures is a major issue for researchers and engineers. The hierarchical void element with the integrals of Legend polynomials is used to characterize the fracture behavior of unpatched crack as well as repaired crack with bonded composite patches by computing the stress intensity factors and stress contours at the crack tip. The numerical approach is based on the v-version degenerate shell element including the theory of anisotropic laminated composites. Since the equivalent single layer approach is adopted in this study, the proposed element is necessary to represent a discontinuous crack part as a continuum body with zero stiffness of materials. Thus the aspect ratio of this element to represent the crack should be extremely slender. The sensitivity of numerical solution with respect to energy release rate, displacement and stress has been tested to show the robustness of hierarchical void element as the aspect ratio is increased up to 2000. The stiffness derivative method and displacement extrapolation method have been applied to calculate the stress intensity factors of Mode I problem.

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이상경상돌기증의 치험례 (A CASE OF SURGICAL TREATMENT FOR SYMPTOMATIC ELONGATED STYLOID PROCESS)

  • 김창환;김은관;박효상;박노부;이용오
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제16권3호
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    • pp.348-355
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    • 1994
  • Styloid process is a slender pointed bone of variable length, which project downward, forward, and slightly medialward from the posteroinferior portion of the tympanic part of the temporal bone. Embryologically, the styloid process is derived from Reichert's cartilage, a structure of second branchial arch origin. Most patients with elongated styloid process remain asymptomatic, but some patients complain pain and sensation of foreign body in the throat, dysphagia, dysphonia, referred otalgia. Recently, we have experienced a case of elongated styloid process in a fifty-nine year old man. He had been suffered from Rt. side sore throat, headache and pharyngeal discomfort during head movement. Through various X-ray examination, Xeroradiography, and palpation of tonsillar fossa, elongated styloid process on Rt. side was confirmed. Under the general anesthesia, it was successfully removed out via transoral approach technique, described by Eagle. The resected styloid process was 2.5cm in it's length and he was freed from the symptoms without further complication.

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인장계류식 해양구조물의 구조응답에 미치는 굽힘강성의 영향 (Effects of the Flexibility on the Structural Responses of a Tension Leg Platform)

  • 이창호;이수룡
    • 한국해양공학회지
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    • 제21권4호
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    • pp.38-44
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    • 2007
  • The structural response characteristics of Tension leg platforms(TLPs) in waves are examined for presenting the basic data for structural design of TLPs. The numerical approach is based on a combination of the three dimensional source distribution method and the structural response analysis method, in which the superstructure of TLP is assumed to be flexible instead of rigid. Hydrodynamic and hydrostatic forces on the submerged surface of a TLP have been accurately calculated by excluding the assumption of the slender body theory. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in structural analysis. The mooring forces are estimated as the sum of pretension of tendons and variational tension due to longitudinal displacements. Stiffness matrices of elastic beam elements connecting nodes are formulated by ordinary method of three dimensional frame analysis. The equation of motion about the whole structure is obtained by the sum of forces and moments acting on each nodes.