• Title, Summary, Keyword: Incident wave

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Effect of Incident Angle of Wave on Floating Pontoon and Moment Resisting Frame (파랑 입사각이 장방형 플로팅 함체와 상부 골조에 미치는 효과)

  • Lee, Young-Wook;Kim, Bo-Ram
    • Journal of Navigation and Port Research
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    • v.37 no.2
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    • pp.221-229
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    • 2013
  • To find the influence of incident angle of wave on the moment of 3 storied steel moment resisting frame which is placed on the concrete rectangular pontoon, the fluid dynamic analysis is carried out, varying the period of wave from 5 to 15 second by 2 seconds. As increasing incident angle of wave to longitudinal axis, the influence of RAO-rolling is increased. The moment of longitudinal frame is increased apparently by the wave pressure when the incident angle is $0^{\circ}$. And the moment of the frame due to the wave pressure is decreased as the incident angle is increased. But the moment of frame due to acceleration caused from pitching and rolling is increased. It is shown that the increased moment when incident angle is $90^{\circ}$ is much greater than that of incident angle $0^{\circ}$.

2D Computational Analysis of Overtopping Wave Energy Convertor

  • Liu, Zhen;Hyun, Beom-Soo;Jin, Ji-Yuan
    • Journal of Ocean Engineering and Technology
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    • v.23 no.6
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    • pp.1-6
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    • 2009
  • An Overtopping Wave Energy Convertor (OWEC) is an offshore wave energy convertor used for collecting overtopping waves and converting the water pressure head into electric power through hydro turbines installed in a vertical duct affixed to the sea bed. A numerical wave tank based on the commercial computational fluid dynamics code Fluent is established for the corresponding analysis. The Reynolds Averaged Navier-Stokes equation and two-phase VOF model are utilized to generate the 2D numerical linear propagating waves, which are validated by the overtopping experiment results. Calculations are made for several incident wave conditions and shape parameters for the overtopping device. Both the incident wave periods and heights have evident effects on the overtopping performance of the OWEC device. The computational analysis demonstrates that the present overtopping device is more compatible with longer incident wave periods.

Realization of Scattering Acoustic Holography using Plane-wave Decomposition (평면파 분리 방법을 이용한 산란 음향 홀로그래피의 구현 방법론)

  • Lee, Seung-Ha;Kim, Yang-Hann
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.498-501
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    • 2006
  • When an object or objects, rigid or flexible, presents in incident sound field, the sound wave is scattered. This, we call, is scattered sound field. It, of course, depends on the amplitude and the direction of the incident sound field as well as the geometry and the surface impedance of the scatterer(object). This paper addresses the way to measure scattered sound field by using arbitrary incident sound wave. This means that the method can decompose the scattered field from measured sound field with respect to any magnitudes and directions of incident plane-waves.

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Numerical Analysis of Waves Profiles coming with Oblique Angle to Permeable Submerged Breakwater on the Porous Seabed

  • Kim, Nam-Hyeong;Woo, Su-Min
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • pp.275-276
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    • 2013
  • This analysis method is based on the wave pressure function with the continuity in the analytical region including fluid and porous structures. Wave profiles coming with oblique angle to permeable submerged breakwater on the porous seabed are computed numerically by using boundary element method. When compared with the existing results for the oblique incident wave, the results of this study show good agreement. The results indicate that wave profiles own high dependability regarding the change of oblique incident waves and permeable submerged breakwater on the porous seabed. Therefore, the analysis method of this study are estimated to be applied as an accurate numerical analysis referring to oblique incident waves and permeable submerged breakwater on the porous seabed in real sea environment.

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Wave Overtopping Reduction Coefficient of Vertical Wall for Obliquely Incident Waves (경사입사파에 대한 직립구조물에서의 월파량 저감계수)

  • Kim, Young-Taek;Lee, Jong-In;Cho, Yong-Sik;Ha, Tae-Min
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.22 no.3
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    • pp.149-155
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    • 2010
  • The existing formula for estimating the wave overtopping are mainly about the perpendicularly incident wave to the structure and wave overtopping formula for the obliquely incident wave are rare. Moreover, these formula present only the overtopping reduction factor(${\gamma}_{\beta}$) with respect to the incident wave angle rather than the spatial distribution of overtopping along the structures because the length of model is relatively too short for the wave to propagate along the structure. In this study, the wave overtopping reduction factor considering the spatial variation of wave overtopping along the vertical wall is investigated using the hydraulic model tests and the results are compared with the those of EurOtop(2007). The wave overtopping reduction factor is modified for ${\beta}$ > $45^{\circ}$ condition.

Effects of Stem Wave on the Vertical Breakwater (해안구조물 전면의 Stem Wave 특성에 관한 연구)

  • 박효봉;윤한삼;류청로
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • pp.138-143
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    • 2001
  • Based on mild slope equation and parabolic approximation the forward diffraction of monochromatic waves by a straight breakwater are studied numerically. The characteristics and effects of stem wave along breakwater and the relations between the stem wave and incident wave angle are discussed.

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Analysis of Impact Factors for the Wave Transmission in the Narrow Channel Sea (수로형 해역에서의 파랑전달에 미치는 영향인자 분석)

  • Lee, Gyong-Seon;Yoon, Han-Sam;Ryu, Cheong-Ro;Park, Jong-Hwa
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • pp.303-308
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    • 2003
  • In this paper, wave numerical modeling was experimented for the analysis of impact factors for the wave transmission as the incident wave and topographic conditions in the narrow channel sea. Recently, Although the results of many researcher for the wave modelling, numerical equations have limited to simulation of wave transformation effects. Despite of thispresent problems, the models was used to design the coastal structures in barrow channel sites. Finally, this paper estimated the wave model(mild slope eq. model) as the analysis of the wave energy transmission according to changing of impact factors(width of channel, bottom slope in channel, incident wave angle, wave period). As the results of numerical experiment, the major impact factors which influence to wave energy transmission were the width of channel and incident wave direction. But in the case that the width of channel is larger than 3L(L=Length of wave), the reduction of wave energy was small.

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Reflection and Hydraulic Characteristics inside Two-Chamber Vertical Slit Caisson in 3-D Oblique Wave Field (3차원 경사입사파동장에서 이중유공슬릿케이슨 내부의 수리특성 및 반사특성)

  • Hur, Dong-Soo;Lee, Jun;Lee, Woo-Dong
    • Journal of Ocean Engineering and Technology
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    • v.28 no.3
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    • pp.227-235
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    • 2014
  • Using a 3-D numerical scheme (LES-WASS-3D) that considered wave-structure-sandy seabed interactions in a 3-D wave field, we analyzed the wave reflection and hydraulic characteristics inside a slit caisson with two chambers in a 3-D oblique wave field. To verify the 3-D numerical analysis method suggested in this study, we compared the numerical results with existing experimental results and found good agreement. The numerical analysis revealed that a standing wave field is generated on the front side of the slit caisson due to the effect of wave reflection. For incident waves propagating perpendicular to the slit caisson, the nodes and anti-nodes of the standing wave are apparent and symmetrical. However, in an oblique wave field, as the incident wave angle decreases, the nodes and anti-nodes of the standing wave become ambiguous and unsymmetrical. It was also found that the wave reflection coefficient decreases as the incident wave angle decreases. It can be pointed out that as the incident wave angle decreases, the turbulent intensity in the chamber increases. Thereby, the increased wave energy dissipation by the increased turbulent intensity reduces the rate of wave reflection. In addition, a strong turbulent intensity generally occurs in the first chamber.

Characteristics of Optical Phase Conjugate Wave Generated by Self-Pumping in Photorefractive $BaTiO_3$ Single Crystal ($BaTiO_3$ 광굴절 결정에서 자기 펌핑에 의해 발생되는 위상공액파의 특성)

  • 이장두
    • Proceedings of the Optical Society of Korea Conference
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    • pp.157-161
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    • 1990
  • Self-pumped phase conjugation(SPPC) in BaTiO3 single crystal is experimentally investigated at a wavelength of 514.5nm from an Ar+ laser. The incident Gaussian beam enters the crystal as an extraordinary ray. The maximum SPPC reflectivity of 48% is obtained at incident angle 80 degree. the SPPC wave demonstrates good image reconstruction. The response time (r) of SPPC wave as a function of incident intensity is measured to be r=36$\times$I-0.79sec.

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3D Incident Wave Response of Structures on Layered Media (다층 반무한 지반-구조물계의 입사파 응답해석)

  • Kim, Moon-Kyum;Cho, Woo-Yeon;Koh, Jae-Pil
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.317-324
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    • 1999
  • Dynamic interaction analysis of surface structure on layered half-space is performed in frequency domain under incident wave excitation. This present study adopts a coupling method that combines the finite element(FE) for the flexible structures and boundary element(BE) for the layered half-space. A semi-analytical approach is employed to reduce the integration range of wavenumbers in the BE formula. For the incident wave input, the response is decomposed and formulated after the impedance matrix for the structure system. Numerical examples are presented to demonstrate the accuracy of the method. The examples show the feasibility of an extended application to the complicated dynamic analysis of structures on layered media under incident wave excitation.

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