• Title/Summary/Keyword: Shallow water wave

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Comparison of Edge Wave Normal Modes (Edge Wave 고유파형의 비교)

  • Seo, Seung Nam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.25 no.5
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    • pp.285-290
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    • 2013
  • Both full linear and shallow water edge waves are compared to get a better understanding of edge wave behavior. By using method of separation of variables, we are able to get solution of full linear edge wave presented by Ursell (1952) without derivation. The shallow water edge waves show dispersive features despite being derived from shallow water equations. When bottom slope is mild enough, shallow water edge wave tends to linear edge wave and has some advantages of manipulation. Solution of edge wave generated by a moving landslide of Gaussian shape is constructed by an expansion of shallow water normal modes. Numerical results are presented and discussed on their main features.

A Study on the Resistance Characteristics of High-Speed Ship in Shallow Water Condition (천수영역에서 고속선박의 저항특성에 대한 연구)

  • 권수연;이영길
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.2
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    • pp.1-11
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    • 2004
  • In this paper, the resistance characteristics of high-speed ship are studied in the region of shallow water condition. For the purpose of this research, model tests in a ship model basin are carried out with an equipment for the satisfaction of shallow water condition, and the computions of wave resistance characteristics and the flow simulations around a ship hull are performed by Michell's thin ship theory and a finite difference method based on MAC scheme, respectively. The calculation results for the resistance and flow characteristics of a ship hull are compared with those from the model tests in deep and shallow water conditions. From the comparison results, it is known that the variation of wave pattern around a ship hull caused by shallow water condition has the most influence to the resistance characteristics of a high-speed ship advancing on shallow water.

TRAVELING WAVE SOLUTIONS FOR A SHALLOW WATER MODEL

  • Jung, Soyeun
    • Honam Mathematical Journal
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    • v.39 no.4
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    • pp.649-654
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    • 2017
  • In this note, we seek traveling wave solutions of a shallow water model in a one dimensional space by a simple but rigorous calculation. From the profile equation of traveling wave solutions, we need to investigate the phase portrait of a one dimensional ordinary differential equation $\tilde{u}^{\prime}=F(\tilde{u})$ connecting two end states of the traveling wave solution.

Numerical Simulation of Longshore Current due to Random Sea Waves (불규칙파에 의한 연안류의 수치계산)

  • 권정곤;양윤모
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.4 no.2
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    • pp.72-82
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    • 1992
  • To accurately estimate nearshore current in shallow water regions. it is necessary to investigate the irregular wave transformation characteristics and radiation stress produced by random sea waves. This research is to investigate the application or the individual wave Analysis Method. the Component Wave Analysis Method and Representative Wave Analysis Method in the shallow water region. These methods were estimated by wave shallowing transformation when the waves propagate from deep water to shallow water region b)r generating regular waves, two component waves and irregular waves (Bretschneider-Mitsuyasu type). That is, the Indivisual Wave Analysis Method is to investigate from the viewpoint of shallow water transformation of wave statistical characteristics and their zero-down-crossing waves (wave height period and wave celerity). And the component Wave Analysis Method is to investigate from the view point of shallow water transformation of basic frequency component wave and their interference frequency component wave. In addition, this research is to compare the measured mean water level elevation with the calculated one from radiation stress of irreguar waves that is assumed in the three methods above.

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A Study on the Numerical Calculation for Wind Waves During the Passage of Typhoon 'Memi' (태풍 '매미' 내습시 파랑선정에 관한 기초적 연구)

  • LEE GYONG-SEON;KIM HONG-JIN;YOON HAN-SAM;RYU CHEONG-RO
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.229-234
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    • 2004
  • A Typhoon wave is generated by wind fields during the Passage of Typhoon. Transporting wind field makes wind wave and swell in the open sea, and then, those wave components are transported in the shallow water. Typhoon waves in the shallow water is generated by Typhoon wind field and incident wave. Bisides, Incident waves to the shallow water are deformated by topographic conditions. This paper estimated the analysis of the Typhoon waves by wind fields and incident waves according to wave action balance equation model. As the result of wave numerical experiment, wave field during the passage of Typhoon 'Memi' in the shallow water is strongly effect by wind fields. Wave action balance equaion can be partially used for Typhoon wave simulations.

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Shallow Water Wave Hindcasting by the Combination of MASCON and SWAN Models (지형을 고려한 해상풍 모델(MASCON)과 SWAN 모델의 결합에 의한 천해파랑 산정)

  • Kim, Ji-Min;Kim, Chang-Hoon;Kim, Do-Sam;Hur, Dong-Soo
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.1
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    • pp.57-65
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    • 2007
  • Shallow water waves are hindcasted from sea wind fields, which include wave transformations such as shoaling, refraction, diffraction, reflection and wave breaking. In case of estimating sea wind field in shallow water, the sea wind revised from free wind obtained by the typhoon model is widely used. However, this method is not able to consider the effect of land topography on the wind field, which will be important factor for shallow water wave forecasting and hindcasting. In this study, therefore, the effect of land topography on sea wind field in shallow water is investigated for shallow water wave forecasting and hindcasting with high accuracy. The 3-D MASCON model is introduced to consider the influence of land topography on the wind field. And, for two areas divided by the topographical characteristics, i.e. shielded and opened coastal areas, sea wind field is examined by comparison between initial wind field by typhoon model and modified wind field by 3-D MASCON model. Finally, applying these sea wind fields to SWAN model, the results of shallow water wave calculated in shielded and opened coastal areas are compared, and, also, the effect of MASCON model on shallow water wave forecasting and hindcasting is discussed.

Experimental studies of impact pressure on a vertical cylinder subjected to depth induced wave breaking

  • Vipin, Chakkurunnipalliyalil;Panneer Selvam, Rajamanickam;Sannasiraj Annamalaisamy, Sannasiraj
    • Ocean Systems Engineering
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    • v.12 no.4
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    • pp.439-459
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    • 2022
  • This paper describes experimental studies of impact pressure generated by breaking regular waves in shallow water on a vertical cylinder. Experimental work was carried out in a shallow water flume using a 1:30 - scale model of a vertical rigid circular hollow cylinder with a diameter 0.2 m. This represents a monopile for shallow water offshore wind turbines, subjected to depth induced breaking regular waves of frequencies of 0.8 Hz. The experimental setup included a 1 in 10 sloping bed followed by horizontal bed with a constant 0.8 m water depth. To determine the breaking characteristics, plunging breaking waves were generated. Free surface elevations were recorded at different locations between the wave paddle to the cylinder. Wave impact pressures on the cylinder at a number of elevations along its height were measured under breaking regular waves. The depth-induced wave breaking characteristics, impact pressures, and wave run-up during impact for various cylinder locations are presented and discussed.

A Study on the Numerical Calculation for Shallow Water Waves Considering the Wind Direction Characteristics of Typhoon (태풍의 풍향특성을 고려한 천해파 산정에 관한 연구)

  • Lee, Kyung-Seon;Kim, Jung-Tae;Ryu, Cheong-Ro
    • Journal of Ocean Engineering and Technology
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    • v.21 no.1 s.74
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    • pp.1-6
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    • 2007
  • While a typhoon is traveling, characteristics of its wind fields are continuously changing, producing severe changes in local water level and wave conditions, especially, when a typhoon comes into shallow water. However, there have not been many studies related to local typhoon effects, especially, considering real time changes of wind direction related to the coastal topography. In the study, the characteristics of the wind field by typhoon and topographical characteristics in shallow water are considered, as well as conditions of wave climate estimation. These are performed by the SWAN (Simulating waves nearshore) model, in order to estimate the growth of wave energy due to the wind field. It can be strongly suggested that the wave energy of theof an inner bay should be estimated when the direction of the bay entrance and the wind direction of the typhoon are identical. The result of the numerical calculations is in better agreement with the observed data than the result of the conventional estimation techniques.

Inundation Analysis Considering Water Waves and Storm Surge in the Coastal Zone (연안역에서 고파랑과 폭풍해일을 고려한 침수해석)

  • Kim, Do-Sam;Kim, Ji-Min;Lee, Gwang-Ho;Lee, Seong-Dae
    • Journal of Ocean Engineering and Technology
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    • v.21 no.2 s.75
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    • pp.35-41
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    • 2007
  • In general, coastal damage is mostly occurred by the action of complex factors, like severe water waves. If the maximum storm surge height combines with high tide, severe water waves will overflow coastal structures. Consequently, it can be the cause of lost lives and severe property damage. In this study, using the numerical model, the storm surge was simulated to examine its fluctuation characteristics at the coast in front of Noksan industrial complex, Korea. Moreover, the shallow water wave is estimated by applying wind field, design water level considering storm surge height for typhoon Maemi to SWAN model. Under the condition of shallow water wave, obtained by the SWAN model, the wave overtopping rate for the dike in front of Noksan industrial complex is calculated a hydraulic model test. Finally, based on the calculated wave-overtopping rate, the inundation regime for Noksan industrial complex was predicted. And, numerically predicted inundation regimes and depths are compared with results in a field survey, and the results agree fairly well. Therefore, the inundation modelthis study is a useful tool for predicting inundation regime, due to the coastal flood of severe water wave.

Wave Simulation on Youngil Bay by WAM Extended to Shallow Water (천해역으로 확장된 WAM모형에 의한 영일만 파랑모의)

  • Chun, Je-Ho;Ahn, Kyung-Mo;Yoon, Jong-Tae
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.6
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    • pp.511-520
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    • 2007
  • WAM(WAve Model), deep water wave model has been extended to the region of shallow water, incorporating wave breaking, and triad wave interaction. To verify the model, numerical simulation of waves in Youngil bay, Pohang is performed and the simulated results show good agreements with measured wave data sets, one station at the mouth of bay and two stations inside the bay. As waves propagate toward the shore, wave height gradually diminishes by bottom friction and wave breaking, and wave direction, initially NE changes normal to the shore due to depth refraction.