• 제목/요약/키워드: cylinder function

검색결과 381건 처리시간 0.028초

2차원 주상체의 강제 동요시 동유체력의 시간 영역 해석법에 관하여 (On the Improved Numerical Method for Hydrodynamic Forces Acting on an Arbitrary Cylinder in the Time Domain)

  • 신영섭;이기표
    • 대한조선학회지
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    • 제27권1호
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    • pp.63-72
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    • 1990
  • 2차원 부유체가 자유 표면상의 평균 위치로 부터 작은 진폭의 비정상 운동을 할 때, 물체에 작용하는 선형 동유체력을 과도 Green 함수를 사용한 적분 방정식법에 의하여 시간 영역에서 수치해석 하였다. 특히 시간 영역에 따라 과도 Green 함수를 급수전개 또는 접근전개시킨 후 사용함으로써, 시간 영역에서 직접해석시에 단점으로 지적되고 있는 수치 계산 소요시간을 단축시켰다. 계산 예로는 원형 단면 주상체의 강제 상하동요 및 수평 동요시의 동유체력을 수치 해석 하였으며, Fourier 변환 후 진동수 영역에서의 해당 값과 비교 도시하였다.

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하이브리드 볼륨 PTV(VPTV) (A New Hybrid Volume PTV)

  • 도덕희;조효제;조경래;문경록;이재민;황태규
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2444-2447
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    • 2008
  • A new 3D-PTV algorithm (a Volume PTV) based upon a hybrid fitness function has been constructed. A coherency fitness function is introduced using the information of space and time to sort out the correct particle pairs between the two camera images. The measurement system consists of two-high-definition-cameras($1k{\times}1k$), a Nd-Yag laser and a host computer. The developed algorithm has been employed to investigate the flow features of the cylinder wake. The Reynolds numbers with the cylinder diameter (d=10mm) are 360, 720, 900 and 1260. Two-dimensional displacements of the particles of each camera's image and neighbouring constraints were introduced to reduce the calculation loads. More than 10,000 instantaneous 3D vectors have been obtained by the constructed algorithm. The constructed algorithm could recover more than $80{\sim}90%$ of the particle numbers in the image.

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On the Evaluation of a Vortex-Related Definite Trigonometric Integral

  • Lee, Dong-Kee
    • 한국해양공학회지
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    • 제18권1호
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    • pp.7-9
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    • 2004
  • Using the solution to th contour integral of the complex logarithmic function ${\oint}_cIn(z-z_{0})dz$, the following definite integral, derived from the formula to calculate the forces exerted to n circular cylinder by the discrete vortices shed from it, has been evaluated (equation omitted)

Slit 近傍의 Stokeslet 에 의한 2次元의 느린 粘性流動 (Two-Dimensional Slow Viscous Flow Due to a Stokeslet Near a Slit)

  • 고형종;김문언
    • 대한기계학회논문집
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    • 제7권4호
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    • pp.386-391
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    • 1983
  • Two-dimensional slow viscous flow due to a stokeslet near a slit is investigated on the basis of Stokes approximation. Velocity fields and stream function are obtained in closed forms by finding two sectionally holomorphic functions which are determined by reducing the problem to Riemann-Hilbert problems. The force exerted on a small cylinder is calculated for the arbitrary position of the cylinder translating in an arbitrary direction. The features of fluid flow are also investigated.

CONDITIONAL FOURIER-FEYNMAN TRANSFORMS OF VARIATIONS OVER WIENER PATHS IN ABSTRACT WIENER SPACE

  • Cho, Dong-Hyun
    • 대한수학회지
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    • 제43권5호
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    • pp.967-990
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    • 2006
  • In this paper, we evaluate first variations, conditional first variations and conditional Fourier-Feynman transforms of cylinder type functions over Wiener paths in abstract Wiener space and then, investigate relationships among first variation, conditional first variation, Fourier-Feynman transform and conditional Fourier-Feynman transform of those functions. Finally, we derive the conditional Fourier-Feynman transform for the product of cylinder type function which defines the functions in a Banach algebra introduced by Yoo, with n linear factors.

다차원 스펙트럼 해석 에 의한 가솔린 엔진 의 진동원 검출 에 관한 연구 (A Study on the Identification of Vibration Sources of a Gasoline Engine by Multi-Dimensional Spectral Analysis)

  • 강명순;오재응;서상현
    • 대한기계학회논문집
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    • 제9권6호
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    • pp.691-698
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    • 1985
  • 본 논문에서는 종래의 FRF법을 이용하였을때의 문제점을 보완하고 계의 정확 한 진동원을 파악하기 위하여 진동원 간에 강한 상관관계가 존재하는 경우에 사용되는 다차원 스펙트럼해석(Multi-Dimensional Spectral Analysis` MDSA)법을 가솔린엔진에 적용 검토하였다.

Device for Assisting Grasping Function

  • Jeong, Gu-Young;Yu, Kee-Ho
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2002년도 ICCAS
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    • pp.77.5-77
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    • 2002
  • A mechanical device was developed for assisting the grasping function of a person whose fingers suffered cervical injury and thus are unable to grasp. This device is composed of a mechanical glove put on the user's hand and a muscle sensor to measure the activity of his or her muscle. The mechanical glove consists of a finger frame, a base and an air cylinder mounted on the base. With the kinematics carefully designed, the finger frame can achieve the grasping motion under the actuation of the air cylinder. For controlling this motion, an innovative sensor was developed to detect the user's motion intention. The sensor measures the change of the muscle stiffness...

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아이스슬러리 제빙장치의 열전달 해석 (Heat Transfer Analysis of Ice Slurry Generator)

  • 신유환;이윤표
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.984-989
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    • 2009
  • The present study has been conducted to predict the temperature distribution in the core of the scraper type ice generator. The analytic model was simplified as the flow in the annular type cylinder, which had an inside wall moving in axial direction due to the rotation of screw and a fixed outside wall. The governing equations were arranged by the method of separation of variables. The results corresponded to the exact solutions of the Bessel function. The qualitative results such as general characteristics of heat transfer in annulus flow from outer cylinder wall to the inside wall were obtained. However the amount of the heat transfer was underestimated as low as $1/5{\sim}1/6$ of the designed value.

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Numerical Solution of the Radiation Problem by the B-Spline Higher Order Kelvin Panel Method for a Half-Immersed Cylinder in Wave and Current

  • Hong, Do-Chun
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2000년도 추계학술대회 논문집
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    • pp.184-188
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    • 2000
  • The improved Green integral equation of overdetermined type applied to the radiation problem for an oscillating cylinder in the presence of weak current is presented. A two-dimensional Green function for the weak current is also presented. The present numerical solution of the Improved Green integral equation by the B-spline higher order Kelvin panel method is shown to be free of irregular frequencies which are present in the usual Green integral equation.

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