• Title/Summary/Keyword: 항주파고

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Prediction of ship wave Crests on Varying Water Depths and Verification by FLOW-3D (변수심에서의 항주파 파형 예측 및 FLOW-3D에 의한 검증)

  • Lee, Byeong Wook;Lee, Changhoon;Kim, Yong Jae;Ko, Kwang Oh
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.4
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    • pp.1447-1454
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    • 2013
  • In this study, we developed the equation of ship wave crests in intermediate as well as deep waters by extending Kelvin's (1887) theory using the recursive relation for the dispersion relation. The present equation can be applied for varying water depth as well as constant water depth. Using FLOW-3D we conducted numerical experiments to verify analytical prediction. The ship wave crest patterns became asymmetric on a plane slope when the ship propagates alongshore direction. That is, in shallower side, wave crests tend to be parallel to the coastline due to refraction and, in deeper side, wave crests tend to be orthogonal due to reverse refraction.

항주파 파고 감쇄의 부소파제에 대한 실해상 실험 연구

  • O, U-Jun;Sin, Jeong-Hun;Park, Tae-Geon;Ham, Yeon-Jae;Jeong, U-Cheol;Park, Je-Ung;Kim, Do-Jeong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2013.06a
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    • pp.118-119
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    • 2013
  • 마리나 시설 내 계류된 선박 및 레저장비를 악천 후 해상상태와 선박 운항에 의해 발생된 파로부터 장비 및 인명의 안전을 위한 파 제거 장치가 필요하다. 본 연구에서는 국내 각 지자체의 수요에 부응하고 시설 및 인명의 안전을 위한 소파 시스템개발을 목적으로 시제품 제작(설계, 해석, 수조시험 등 수행완료)하였다. 실해상 성능시험에서 항주파의 발생을 위해 시험선박 선정하였으며, 소파장치 전후의 파고계측 등을 위해 부가물을 계측하여 파고를 촬영 및 계측하였다. 개발된 소파장치의 실해상 시험임을 감안해 해상 주위의 조류, 풍속, 인근 해역에서 오는 파랑변형 등에 따른 파랑요소를 고려하여 시험하였다. 부소파제는 약 40~80% 의 에너지 감소율을 보였으며, 유의파고 조건에서 42%의 에너지 감소율을 보였다.

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Wave Run-up Characteristics of Ocean Wave, Current, and Kelvin Wave Interaction in the Canal (운하에서 파랑·흐름·항주파의 상호작용에 의한 처오름 특성)

  • Hur, Dong-Soo;Lee, Woo-Dong;Jung, Kwang Hyo
    • Journal of Ocean Engineering and Technology
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    • v.27 no.4
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    • pp.55-61
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    • 2013
  • The numerical simulation using LES-WASS-3D is developed to investigate the wave run-up on the revetment along the canal. Interaction of ocean wave, current, and Kelvin wave is investigated on 40 conditions varying the number of ship, cruising direction, and relative cruising location of ships, when a 650TEU container cruises in the canal. The mean wave run-up heights on the revetment are compared for every simulated conditions. The largest height of wave run-up is generated at the C-pair condition and the wave run-up generated at the canal entrance is larger than that at the inside canal. When Kelvin waves is interacted with the current, the mean wave run-up height is increased approximate 10% compared with no current condition.

Mooring Analysis due to Ship Wave at Gunzang New Port (군장신항만의 항주파로 인한 계류안정성해석)

  • Kim, Jae-Soo;Kong, Byung-Seung;Hong, Nam-Seeg
    • Journal of Ocean Engineering and Technology
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    • v.22 no.5
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    • pp.69-74
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    • 2008
  • This study performed a numerical simulation to predict the development of ship waves and their propagation in the shallow water region of Gunzang New Port and to examine the stability of taut line mooring at the sea wall using the design criteria. In order to predict the propagation of ship waves based on the speeds of various ships under complicated and shallow water depths, a computer model was constructed based on the Boussinesque equation with a fixed coordinate system. Additionally, an investigation if the stability was made by applying MOSES under the environmental loadings estimated by OCIMF.

Stability Analysis of Low Flow Revetments on External Forces (저수호안에 작용하는 외력에 의한 안정성분석)

  • Kim, Chul;Park, Nam-Hee;Kim, Dae-Young;Kim, Yun-Hwan
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.5
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    • pp.147-153
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    • 2008
  • Tractive forces by flowing water and ship generated waves are items that affect the stability of the low flow revetments among various external forces exerting on those revetments. Bank revetment stability by these external forces is analysed in this study. The study area is the section of the test construction area changing the artificial revetments to ecological revetments in Han river. Tractive forces are computed using the calculated flow velocity using RMA-2 model. The stability is analyzed comparing the calculated tractive forces with permissible tractive forces of the revetments in the study area. The calculated tractive forces at section number 93 is higher than permissible tractive forces in that section, so the section is estimated hydraulically unstable. The calculated tractive forces for the storm of 10th August 2007 are small compared to the permissible tractive forces in all sections. The sections are considered to be hydraulically stable, but have been eroded in some parts. The reason for the erosion is considered to have insufficient time for the plants taking root, and be exerted composite forces such as forces by ship generated waves. Ship generated waves by the excursion boats and small boats called river taxi was calculated. Wave forces by these calculated waves are computed and compared with the supporting forces of the revetment material. The external forces exerted by the ships in Han River on the revetments is very little compared with the permissible supporting forces of the revetments, so the revetments are estimated hydraulically stable. But considering the composite forces are exerted simultaneously, the stability consideration should include these composite forces.

Numerical Simulation of the Ship-Induced Waves inside Harbor (항내 항주파 계산을 위한 수치모의)

  • 이화영;권세영;오병철;전인식
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 2003.08a
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    • pp.270-275
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    • 2003
  • 일반적으로 완경사를 가지는 자연해빈은 항내 파랑 에너지를 감쇄시켜 항만의 정온도를 유지시키는 중요한 역할을 한다. 그러나 계속되는 항만개발로 자연해빈이 인공적인 호안이나 안벽 등으로 급속하게 대체되어 가고 있는 실정이다. (중략)

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On Propagation of Ship Induced Waves in 3-D Numerical Wave Basin with Non-Reflected Wave Generation System (3차원 수치파동수조에서 무반사 조파시스템을 이용한 항주파의 전파재현)

  • Lee, Woo-Dong;Hur, Dong-Soo
    • Journal of Ocean Engineering and Technology
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    • v.25 no.6
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    • pp.23-28
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    • 2011
  • In this paper, a new generation method for ship induced waves is proposed using the fully non-linear 3-D numerical model with non-reflected wave generation system (LES-WASS-3D). A ship induced wave generated by the newly proposed method is examined in comparison with that obtained by an empirical formula. It is then shown that there is a good agreement in free surface the elevation between them. As a result, it is revealed that a ship induced wave in a 3-D numerical wave field can be simulated well using LES-WASS-3D.

The Design of Parameters to Improve Actuating Performance in High Frequency Vibro-Hammer(HFVH) and the Study of Characteristic Propagation and Attenuation of Piling Vibration (초고주파 진동항타기의 구동 성능향상을 위한 파라미터 설계 및 항타진동의 전달과 감쇠특성에 관한 연구)

  • Jang, Tae-In;Park, Joon-Hyuk;Baek, Yoon-Su;Kim, Sung-Bae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.6
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    • pp.763-773
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    • 2004
  • This paper suggests the 2 D.O.F mathematical model of the High Frequency Vibro-Hammer (HFVH), introduces an experimental method for measuring of the attenuation of piling vibration and proves what experiments are coincident with the equation of wave propagation. As vibratory installation of piles and casings has many economic merits in the construction field, most of all contractors prefer to vibratory pile driving method than the other. Compared to impact pile driving, vibratory installation has the advantage of reducing vibration or noise pollution and can drive piles under high frequency. Experiments serve estimations of capabilities and limitations of the HFVH's excitation force and finding of sensitivity for important soil resistance parameters. Also, we discuss the HFVH that can drive with three kinds of input waves (triangular, sine and square wave) and propose the design of parameters to improve actuating performance in it.

Analysis of Scattered Fields Using High Frequency Approximations (고주파수 근사 이론을 이용한 결함으로부터의 초음파 산란장 해석)

  • Jeong, Hyun-Jo;Kim, Jin-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.2
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    • pp.102-109
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    • 2000
  • This paper describes two different theories used to model the scattering of ultrasound by a volumetric flaw and a crack-like flaw. The elastodynamic Kirchhoff approximation (EKA) and the geometrical theory of diffraction (GTD) are applied respectively to a cylindrical cavity and a semi-infinite crack. These methods are known as high frequency approximations. The 2-D elastodynamic scattering problems of a plane wave incident on these model defects are considered and the scattered fields are expressed in terms of the reflection and diffraction coefficients. The ratio of the scattered far field amplitude to the incident wave amplitude is computed as a function of the angular location and compared with the boundary element solutions.

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