• 제목/요약/키워드: Slender body

검색결과 192건 처리시간 0.029초

RANS 기반의 세장체 이론을 이용한 선형 조종 유체력 미계수 추정에 관한 연구 (Prediction Method for Linear Maneuvering Hydrodynamic Derivatives Using Slender Body Theory Based on RANS)

  • 이성욱
    • 한국해양공학회지
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    • 제31권5호
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    • pp.340-345
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    • 2017
  • It is important to predict the hydrodynamic maneuvering derivatives, which consist of the forces and moment acting on a hull during a maneuvering motion, when estimating the maneuverability of a ship. The estimation of the maneuverability of a ship with a change in the stern hull form is often performed at the initial design stage. In this situation, a method that can reflect the change in the hull form is necessary in the prediction of the maneuverability of the ship. In particular, the linear hydrodynamics maneuvering derivatives affect the yaw checking motion as the key factors. In the present study, static drift calculations were performed using Computational Fluid Dynamics (CFD) based on Reynolds Average Navier-Stokes (RANS) for a 40-segment hull. A prediction method for the linear hydrodynamic maneuvering derivatives was proposed using the slender body theory from the distribution of the lateral force acting on each segment of the hull. Moreover, the results of a comparison study to the model experiment for KVLCC1 performed by KRISO are presented in order to verify the accuracy of the static drift calculation. Finally, the linear hydrodynamic maneuvering derivatives obtained from both the model test and calculation are compared and presented to verity the usefulness of the method proposed in this study.

세장선 이론에 의한 조파저항의 수치 해석 (Numerical Analysis on the Wave Resistance by the Theory of Slender Ships)

  • 김인철
    • 수산해양기술연구
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    • 제23권3호
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    • pp.111-116
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    • 1987
  • 이상으로부터 다음의 결론을 얻는다. 조파저항 이론의 전개에서 Michell 적분보다 더욱 정밀한 Neumann-Kelvin 문제가 복잡한 kernel 함수 때문에 많은 시간과 노력이 필요하지만, 원점 부근에서 Kelvin 소오스의 점근거동을 조사하여 세장체 근사를 행함으로 N-K 문제의 kernel 함수에 대한 근사와 동등하게 처리될 수 있었다. 조파저항의 계산 결과가 Michell 적분과 비슷한 경향을 보이나, 실험치와의 정확한 비교를 할 수 없었다. 그러나 세장선 이론을 적용함으로써 훨씬 복잡하고 지루한 작업을 들 수 있었다. 전진 속도를 갖는 경우에는 수정된 Green정리를 이용하면 될 것으로 기대된다.

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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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남성 재킷 패턴 설계를 위한 30-44세 남성의 상반신 체형 및 유형별 사이즈 연구 (A study on the upper body type and size of men aged 30-44 for men jacket pattern design)

  • 권동국
    • 복식문화연구
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    • 제29권6호
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    • pp.881-903
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    • 2021
  • This study aimed to analyze adult men's body sizes and shapes and suggest size specifications to provide preliminary data to academia and industries. A total of 814 adult men aged 30-44 were selected from the 7th Size Korea data, and 55 direct upper body measurement and calculation items were analyzed using SPSS 25.0. In individual Individual differences, thickness, circumference, and width were high, and height and length were low. Height above the waist base line and shoulder dimension decreased in early 40s age group, while height below the waist base line declined as age increased. In addition, buttocks shape changes were found in early 40s age group. According to factor analysis, 'upper body and upper-extremity horizontal size', 'torso height and upper extremity length', 'shoulder dimension', 'upper body length' and 'shoulder angle' were derived. Using clustering analysis, four different body types were classified: i) big abdomen with flat chest, ii) slender with big, raised shoulders, iii) dwarfish with small, droopy shoulders, and iv) obese with large shoulders. 'Slender with big, raised shoulders' was a typical body shape among men aged 30-44. In older participants, the 'big abdomen with flat chest' ratio was low, while 'obese with large shoulders' was more common. This study proposed size specifications by body type considering the above characteristics.

오일러 매개변수를 이용한 해양 세장체 대변위 거동 해석 (Euler Parameters Method for Large Deformation Analysis of Marine Slender Structures)

  • 홍섭
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2003년도 춘계학술대회 논문집
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    • pp.163-167
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    • 2003
  • A novel method for 3-dimensional dynamic analysis of marine slender structure gas been developed by using Euler parameters. The Euler parameter rotation, which is being widely used in aerospace vehicle dynamics and multi-body dynamics, has been applied to elastic structure analysis. Large deformation of flexible slender structures is described by means of Euler parameters. Euler parameter method is implemented effectively in incremental-iterative algorithm for 3D dynamic analysis. The normalization constraint of Euler parameters is efficiently satisfied by means of a sequential updating method.

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의복스타일과 색이 신체이미지 지각에 미치는 영향 (The Effects of Clothing Styles and Colors on a Body Image Perception)

  • 김효숙;최창석;이은실
    • 대한가정학회지
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    • 제41권9호
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    • pp.135-148
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    • 2003
  • The purpose of this study was to examine the effect of clothing colors, clothing styles on women's body image perception. The experimental design was 2${\times}$2${\times}$9(perceiver's gender ${\times}$clothing styles${\times}$clothing colors) factorial design with between-subjects design. Subjects were 320 college students in the metropolitan area of Seoul. Perceiver's gender, clothing styles, and clothing colors gave a significant influence on the 3 variables of shoulder, the upper half of the body, and bust. Shoulder and the upper half of the body had an interaction effect by clothing styles and clothing color. Perceiver's gender gave a significant influence on hip size, length of leg, height, clothing styles did a significant influence on hip size, length of leg, height, and slender figure. Clothing colors gave a significant influence on length of leg, height, and slender figure. Length of leg and slender figure had an interaction effect by perceiver's gender and clothing styles. Hip size had an interaction effect by perceiver's gender and clothing color. Hip size had an interaction effect by clothing styles and clothing color. The results of this study support that coloration of clothing and clothing style affects perception of stimulus persons wearing apparel.

First Records of Two Spirostomum Ciliates (Heterotrichea: Heterotrichida: Spirostomidae) from Korea

  • Jang, Seok-Won;Kwon, Choon-Bong;Shin, Mann-Kyoon
    • Animal Systematics, Evolution and Diversity
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    • 제28권1호
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    • pp.29-35
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    • 2012
  • Two Spirostomum species collected from freshwater in Korea were identified as S. caudatum (Muller, 1786) and S. teres (Claparede and Lachmann, 1858). They are recorded for the first time in Korea. The description was based on the observation of living specimens and protargol impregnated specimens. Diagnostics of these species are as follows. Spirostomum caudatum: body size $400-450{\times}20-30\;{\mu}m$ in vivo, shaped long and slender with a tapered posterior part, highly contractile; macronucleus ellipsoid; adoral zone of membranelles occupied 30% of body length; somatic kineties 14-22 in number. Spirostomum teres: body size $240-460{\times}25-40\;{\mu}m$ in vivo, shaped long and slender with a flattened posterior end, highly contractile; cortical granules arranged in 2-3 rows; adoral zone of membranelles occupied 50% of body length; somatic kineties 20-30 in number; macronucleus ellipsoid; micronuclei 2-3 in number. Spirostomum caudatum and S. teres are the most similar congeners, but they are different in the posterior part of body (tail-like posterior part vs. flattened posterior end), length of adoral zone of membranelles in body length (1/3 vs. 1/2), and the number of somatic kineties (14-22 vs. 20-30). These populations match with European populations in morphological characters.

First Record of Two Spirostomum Species (Spirostomatidae, Heterotrichida, Heterotrichea) of Ciliates from Jindo Island in Korea

  • Kim, Min Seok;Kim, Ji Hye;Shin, Mann Kyoon
    • Animal Systematics, Evolution and Diversity
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    • nspc9호
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    • pp.1-9
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    • 2016
  • Two Spirostomum species were collected from freshwater in Jindo Island, Korea and identified as Spirostomum ambiguum (Muller, 1786) Ehrenberg, 1835 and Spirostomum minus Roux, 1901. This study is the first known morphological record of these two species being found in Korea. The description is based on the observation of living specimens and protargol impregnated specimens. Diagnostics of Spirostomum ambiguum: body size $340-930{\times}45-80{\mu}m$ in vivo; long and slender body with truncated posterior part; macronucleus moniliform with 7-22 nodules; cortical granules irregularly arranged 4-5 rows in between somatic kineties; 24-58 somatic kineties arranged longitudinally; adoral zone of membranelles (AZM) covered about 60-80% of body length. Diagnostics of Spirostomum minus: body size $500-730{\times}35-45{\mu}m$ in vivo; long and slender body with truncated posterior part; macronucleus moniliform with 11-16 nodules; micronucleus 20-37 oval shape; cortical granules regularly arranged 3-4 rows in between somatic kineties; 20-30 somatic kineties arranged longitudinally; AZM covered about 40-50% of body length with 120-150 adoral membranelles.

중년여성의 신체부위 인지유형에 따른 신체만족도와 착의 의복 스타일 (Body Cathexis and Actual Clothing Styles of Middle-aged Women According to Perception of Their Body)

  • 위은하;박우미
    • 한국의류학회지
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    • 제27권9_10호
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    • pp.1112-1123
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    • 2003
  • This study is designed for improving wearing styles for middle-aged women who are in unsatisfactory body types and also providing the basic information about the suitable clothing designs for them. This study focuses on what kinds of body types they perceive, what the differences are between the perception of their body types and the real ones, and how the actual clothing styles can be affected by those perceived body types. This study is based on the survey of the perception of body types, the clothing styles, and the satisfaction level of body cathexis, while measuring body size of each person responded. The data were analyzed by Mean, ANOVA, Duncan-test of SPSS Win. (ver 10.1)program. The results are as follows: 1. The perception of their body types can be categorized into three clusters, the obesity, the arm & leg obesity, the slender. 2. By and large, Middle-aged women perceive their body types exactly what they we. However, they show a relatively subjective view on the upper arm girth, ankle girth, and arm length 3. The abdomen is at the lowest satisfactory part in body cathexis for the entire groups responded, and there are some differences among the perception of their body types in whole body silhouette and trunk. 4. Middle-aged women who perceive themselves as a bit slender show a tendency of having tight and revealing clothing styles, while the obese who perceived themselves wouldn't take them as appropriate dresses.

익동체(翼胴體)의 공력탄성학적특성(空力彈性學的特性)에 관한 연구(硏究) (On the Aeroelastic Characterisrics for the Flight Vehicle of Wing-Body Combination)

  • 이해경
    • 대한조선학회지
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    • 제10권1호
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    • pp.27-32
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    • 1973
  • This paper shows the method for obtaining the body flutter velocity and frequency for flight body which consists of low aspect ratio wing and body combination by assuming slender body of cylinderical shell structure. The stiffness matrix of the cylinderical shell is represented from Donnel eq. by the finite difference method, and also unsteady aerodynamic influence matrix is represented by the Doublet Lattice Method of Albano & Rodden. The flutter matrix can be obtained from those matrices.

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