• Title/Summary/Keyword: 소오스-다이폴

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Hydroelastic Responses for a VLFS close to a Breakwater by the Velocity Potential Continuation and Singularity Distribution Method (속도포텐셜접속법과 특이점분포법에 의한 방파제에 근접한 부유식 해상공항에 대한 유탄성 응답 해석)

  • Ho-Young Lee;Young-Ki Kwak;Jong-Hwan Park
    • Journal of the Society of Naval Architects of Korea
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    • v.39 no.2
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    • pp.11-18
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    • 2002
  • In this paper, the method calculating hydroelastic responses of very large floating structure close to a breakwater in waves is presented. The source-dipole distribution method is used to calculate the generalized radiation problem considering breakwater effects and the diffraction problem is analyzed by using the source-dipole distribution andvelocity potential continuation method. The response of a VLFS is approximated by anexpansion in terms of a free-free beam. Calculated model is a VLFS with 1000m in length in a sea with a straight breakwater. The vertical displacements and bonding moments around a VLFS are calculated by variations for distance between a VLFS and a breakwater and incident wave angle to know the effect of a breakwater.

Analysis of Hydroelastic Responses for Very Large Floating Structures with a Shallow Draft (천흘수 초대형 부유식 해양규조물의 유탄성 응답해석)

  • 신현경
    • Journal of Ocean Engineering and Technology
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    • v.14 no.2
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    • pp.53-59
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    • 2000
  • A numerical method to predict responses of very large floating structures in wave is suggested using source-dipole distribution method. The deflection of the plate is calculated by the finite element method in terms of rigidity matrix of each node. The calculated results for a plate are compared with the experimental ones.

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The Center Locus Estimation of the Evoked Potential Distributions During Visual Stimulation in Human (시각 자극 동안의 유발성 전위분포 의 중심점 추적에 관한 연구)

  • Park, Gwang-Seok;Min, Byeong-Gu;Lee, Chung-Ung
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.20 no.3
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    • pp.6-12
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    • 1983
  • The visual evoked potentials were measured using 19 electrodes attached to the scalp in 5 normal and 4 abnormal subjects during visual stimulation and these data were sampled for computer processing with 500 Hz sampling frequency. The center of potential distributions and its time-dependent locus were estimated from these potential distributions using weighting matrix which was determined by the electrodes' position coordinates. In normal subjects these estimated electrical signals were shown to propagate from the frontal lobe to the occipital lobe of the cortex following the known visual pathway. In abnormal subjects, there were significant differences in these estimated propagation pathway. The relationships among this model, the point source model and the dipole source model were analyzed.

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Hydroelastic Responses of the Floating Airport Considering the Shape for Control Tower (관제탑 형상을 고려한 부유식 해상공항의 유탄성 운동)

  • 이호영;곽영기;박종환
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.10a
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    • pp.196-201
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    • 2001
  • Very Large Floating Structures have been planned for effective utilization of ocean space in recent years. The VLFS usually has a control tower to guide airplane securely. This paper present an effective method for calculating the wave induced hydroelastic responses of VLFS considering the effect of control tower-shapes. The source and dipole distribution method is used to calculate the hydrodynamic loads and equation of motion is derived by considering the static and dynamic coupling effects from different segments of the plate. The rigidity matrix for VLFS is formulated by finite element method using a plate theory. The calculated results for VLFS with a control tower are compared with those for VLFS without a control tower.

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Trial Design of a Very Large Floating Airport (General Arrangement and Decision of Depth) (초대형 부유식 해상공항의 시설계 (일반배치와 깊이 결정))

  • 신현경;임춘규;정재희
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.10a
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    • pp.45-49
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    • 2001
  • The length and the breadth or a very large floating airport are determined by airplane types and airport facilities. However, the depth affect not only the structural strength but also the functional requirement such as a possibility of taking off and landing. The optimization problem for determining the depth is to select a design so that the cost is minimized. In this paper, a general arrangement and a method to decide the depth are proposed. Strength, functional requirement, and possibility of occurrence of deck wetness and slamming are considered in order to determine the depth of structure. Hydrodynamic forces of the diffraction and radiatin problems are predicted by applying the source-dipole distribution method, and the structural responses are obtained by the finite element method.

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Nonlinear Motion Responses of a Moored Ship beside Quay (안벽에 계류된 선박의 비선형 운동응답)

  • 이호영;임춘규;유재문;전인식
    • Journal of Ocean Engineering and Technology
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    • v.17 no.4
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    • pp.8-15
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    • 2003
  • When a typoon sets into harbour, a moored ship shows erratic motions and even mooring line failure may occur. such troubles may be caused by harbour resonance phenomena, resulting in large motion amplitudes at low frequency, which is close ti the natural frequency of th moored ship. The nonlinear motions of a ship moored to quay are simulated under external forces due to wave, current including mooring forces in time domain. The forces due to waves are obtained from source and dipole distribution method in the frequency domain. The current forces are calculated by using slow motion maneuvering equation in the horizontal plane. The wind forces are calculated from the empirical formula of ABS and the mooring forces of ropes and fenders are modeled as linear spring.

Motion Analysis of a Very Large Floating Structure in Irregular Waves (불규칙파 중 초대형 부유식 해양 구조물에 대한 운동 해석)

  • 신현경;이호영;임춘규;신현수;박인규
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.04a
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    • pp.63-68
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    • 2000
  • A very large floating structure has rather small motion characteristics as to the whole body, while the motion at end part of such structure becomes largest due to the elastic motion of the structure. This paper presents on the theoretical result on the relative motion characteristics and green water phenomena of VLFS in waves This phenomena affect not only to strength of the structure but also the determination of depth of structure. To predict motion responses of structure in regular waves, the source-dipole distribution method and F.E.M is used By irregular wave results, the probability of occurrence of green water and response of the structure were calculated.

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Transient Responses of an Airplane Taking off from and Landing Very Large Floating Stricture in Waves (항공기 이 .착륙 시 초대형 부유식 해양구조물의 시간 영역 응답 해석)

  • 신현경;이호영;임춘규;강점문;윤명철
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.10a
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    • pp.63-67
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    • 2000
  • Up to this day, Most studies of hydroelasticity are inclined to frequency domain atnlysis. Thos amlysis Q the landing, take-4, and dropping of airaqft on a structure. So, the concern of this prrper is a tra a VLFS subjected to dymmic lazd induced by airplane larndirrg and take-off. To predict added mass, dampr exciting force, the source-dipole distribution method were used The responses are accomplished by Fdoimain analysis method is based on Newmark $\beta$ method to pursuit time step pnzcedure taking advantage function for hvdrodvnumic effects.

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Hydroelastic Responses of Nonerctangular Floating Airports Considering the Shape of Control Tower (관제탑 형상에 의한 불균일한 부유식 해상공항의 유탄성 운동)

  • 이호영;곽영기;박종환
    • Journal of Ocean Engineering and Technology
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    • v.16 no.2
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    • pp.32-37
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    • 2002
  • Very Large Floating Structures have been planned for effective utilization of ocean space in recent years. The nonerctangular VLFS usually has a control tower to guide airplane securely. This paper presents an effective method for calculating the wave induced hydroelastic responses of VLFS considering the effect of control tower-shapes. The source and dipole distribution method is used to calculate the plate. The rigidity matrix for VLFS is formulated by finite element method using a plate theory. The calculated results for nonerctangular VLFS with a control tower are compared with those for VLFS without a control tower.

Transient Responses of an Airplane Taking off from and Landing on a Very Large Floating Structure in Regular Waves (규칙파중 항공기 이.착륙시 초대형 부유식 해양구조물의 천이 응답 해석)

  • 신현경;이호영;임춘규;강점문;윤명철
    • Journal of Ocean Engineering and Technology
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    • v.15 no.1
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    • pp.26-30
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    • 2001
  • Up to now, Most studies of hydroelasticity are about frequency domain analysis. Those aren't suited for analysis of the landing take-off, and dropping of aircraft on a structure. So, the concern of this paper is the transient behavior of a VLFS subjected to dynamic load, induced by airplane landing and take-off. To predict the added mass, damping coefficient, and wave exciting force, the source-dipole distribution method was used in the frequency domain. The responses are accomplished by using the FEM scheme. A time domain analysis method is based on the Newmark β method to pursue the time step procedure, taking advantage of memory effect function for hydrodynamic effects.

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