• Title/Summary/Keyword: Maximum wave height

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Characteristics of Wave Propagation by Water Level Conditions at Wando Sea Area: Numerical Modeling (완도 해역의 해수면 조건에 따른 파랑 변형 특성)

  • Jeon, Yong-Ho;Yoon, Han-Sam;Kim, Dong-Hwan;Kim, Won-Seok;Kim, Heon-Tae
    • Journal of Fisheries and Marine Sciences Education
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    • v.25 no.1
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    • pp.1-11
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    • 2013
  • The aim of this study was estimated the characteristics of the wave propagation by the water level conditions using a numerical modeling method at the Wando sea area. For three cases numerical simulation on the condition of incident and incoming of the deepwater design wave and the season normal wave, the spatial distribution of the incident wave at study area were investigated. And the calculated numerical modeling results were compared with measured field wave data. According to on-site wave data measured for 18 days, the range of the significant wave height and period were 0.10~1.14 m, 4.35~8.74 sec, respectively, and the maximum wave height were 0.15~1.66 m. From the results of numerical model for offshore design wave incident, the wave height attacked from Southern-East direction at this study area were over maximum 10.5 m because of rapidly change of water depth. Numerical modeling by three water level conditions of Approxmate Lowest Low Water Level(Approx. L.L.W), Mean Sea Level(M.S.L) and Approximate Highest High Water Level(Approx. H.H.W) were practiced. From the results for the case of Approx. H.W.L, variations of wave height at the back area of islands were about 1.6 m at maximum value for the case of deepwater design wave incoming. The significant wave heights of winter season were bigger than summer under normal wave condition, the incident wave height over 5.5 m decreased by shielding effect of islands. The change of maximum wave height at summer season were distinct than winter and was about 1.2 m and 0.8 m, respectively.

Experimental study on the tension of cables and motion of tunnel element for an immersed tunnel element under wind, current and wave

  • Wu, Hao;Rheem, Chang-Kyu;Chen, Wei;Xu, Shuangxi;Wu, Weiguo
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.13 no.1
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    • pp.889-901
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    • 2021
  • The tension of cables and motion response significantly affect safety of an immersed tunnel element in the immersion process. To investigate those, a hydrodynamic scale-model test was carried out and the model experiments was conducted under wind, current and wave loads simultaneously. The immersion standby (the process that the position of the immersed tunnel element should be located before the immersion process) and immersion process conditions have been conducted and illustrated. At the immersion standby conditions, the maximum force of the cables and motion is much larger at the side of incoming wind, wave and current, the maximum force of Element-6 (6 cables directly tie on the element) is larger than for Pontoon-8 (8 cables tie on pontoon of the element), and the flexible connection can reduce the maximum force of the mooring cables and motion of element (i.e. sway is expecting to decrease approximate 40%). The maximum force of the mooring cables increases with the increase of current speed, wave height, and water depth. The motion of immersed tunnel element increases with increase of wave height and water depth, and the current speed had little effect on it. At the immersion process condition, the maximum force of the cables decrease with the increase of immersion depth, and dramatically increase with the increase of wave height (i.e. the tension of cable F4 of pontoons at wave height of 1.5 m (83.3t) is approximately four times that at wave height of 0.8 m). The current speed has no much effect on the maximum force of the cables. The weight has little effect on the maximum force of the mooring cables, and the maximum force of hoisting cables increase with the increase of weight. The maximum value of six-freedom motion amplitude of the immersed tunnel element decreases with the increase of immersion depth, increase with the increase of current speed and wave height (i.e. the roll motion at wave height of 1.5 m is two times that at wave height of 0.8 m). The weight has little effect on the maximum motion amplitude of the immersed tunnel element. The results are significant for the immersion safety of element in engineering practical construction process.

A Study on Shape and Height of Shipwaves

  • Gang, Song-Jin;Kim, Mi-Kum;Kim, Chang-Je
    • Journal of Navigation and Port Research
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    • v.33 no.2
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    • pp.105-110
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    • 2009
  • Shipwaves am have harmful effects on ships working on the sea, in a harbour or navigational channel and caused beach erosion, seawall destruction. This study aims to investigate describe the characteristics of the wave pattern generated by an individual model ship tested at different velocities and hull forms for a given water depth and to investigate the variations at a given distance from the sailing line under the same conditions. As a result, the angles a's by model ship tests are smaller than those by real ship ones. Wave heights decreases with an increasing the mid-ship cross sectional area $A_s$. The maximum wave height and period increase rapidly in the subcritical speed, and beyond the critical speed the height and period decrease with increasing depth Froude number. And the period keeps constant with the distance from the sailing line.

Expected Overtopping P개bability Considering Real Tide Occurrence

  • Kweonl, Hyuck-Min;Lee, Young-Yeol;Oh, Young-Min
    • Proceedings of the Korea Water Resources Association Conference
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    • 2004.05b
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    • pp.479-483
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    • 2004
  • A new calculation method of expected overtopping probability of rubble mound breakwater considering real tide occurrence has been proposed. A calculation method of expected overtopping probability of rubble mound breakwater was proposed by Kweon and Suh (2003). In their calculation, the fluctuation of tidal elevation was expressed by the sinusoidal change that yields the uniform distribution of occurrence frequency. However, the realistic distribution of tidal elevation should influence on the overtopping chance. In this study, the occurrence frequency of tidal elevation obtained from the real sea is included. The tidal elevation used in this study is collected from the east coastal part of Korean peninsular. Analyzing the annual data of the tidal fluctuation measured hourly during 355 days, the distribution of occurrence frequency is formulated utilizing by the normal distribution with one peak. Among the calculation procedures of annual maximum wave height, wave height-period joint distribution, wave run-up height and occurrence frequency of tide, only the annual maximum wave height is again chosen randomly from normal distribution to consider the uncertainty. The others are treated by utilizing the distribution function or relationship itself, It is found that the inclusion of the variability of tidal elevation has great influence on the computation of the expected overtopping probability of rubble mound breakwater. The bigger standard deviation of occurrence frequency is, the lower the overtopping probability of rubble mound breakwater is.

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A Study on the Characteristics of the Stem Wave in front of the Coastal Structure (해안구조물 전면의 Stem Wave특성에 관한 연구)

  • PARK HYO-BONG;YOON HAN-SAM;RYU CHEONG-RO
    • Journal of Ocean Engineering and Technology
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    • v.17 no.5 s.54
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    • pp.25-31
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    • 2003
  • Numerical experiments have been conducted using the nonlinear combined refraction-diffraction model, in order to analyze the generation characteristics of stem wave, which is formed by the interaction between vertical structure and the oblique incident waves. The results of stem wave are discussed through the stem wave height distribution along/normal vertical structure, under the wide range of incident wave conditions-wave heights, periods, depths, and angles. Under the same wave height and period, the larger the incident wave angle, the higher the stem wave heights. According to the results of wave height distribution, in front of vertical structure, the maximum of stern wave heights occurs in the location bordering the vertical wall. Furthermore, the most significant result is that stem waves occur under the incident angles between $0^{\circ}\;and\;30^{\circ}$, and the stem wave height ratio has the maximum value, which is approximately 1.85 times the incident wave height when the incident wave angle becomes $23^{\circ}$.

A Study of Matimum Run-up Heights of Periodic Waves (주기파의 최대 처오름높이에 관한 연구)

  • Jo, Yong-Sik;Lee, Bong-Hui
    • Journal of Korea Water Resources Association
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    • v.32 no.6
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    • pp.649-655
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    • 1999
  • The maximum run-up heights of periodic waves are numerically investigated in this study. Incident waves are sinusoidal and enoidal waves. The maximum run-up height of enoidal wave approaches that of sinusoidal wave as the wave length decreases, while it approaches that of solitary wave as the wave length increases. If wave height is fixed, the maximum run up heights of enoidal waves are always greater than those of sinusoidal waves but smaller than those of solitary waves.

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A Study on Shipments of Swimming Crab Using Negative Binomial Regression Model (음이항회귀모형을 이용한 꽃게 출하량에 관한 연구)

  • Nam, Yeongeun;Seo, Jihyun;Choi, Gayeong;Lee, Kyeongjun
    • Journal of the Korean Data Analysis Society
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    • v.20 no.6
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    • pp.2941-2951
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    • 2018
  • The purpose of this paper is to analyse the effect of ocean weather factors on shipments of swimming crab. We use the data of data portal and ocean weather factors (mean wind velocity, mean atmospheric pressure, mean relative humidity, mean air temperature, mean water temperature, mean maximum wave height, mean significant wave height, maximum significant wave height, maximum wave height, mean wave period, maximum wave period). We did statistical analysis using Poisson regression analysis and negative binomial regression analysis. As the result of study, important factors influential in the shipments of swimming crab turn out to be mean wind velocity, mean atmospheric pressure, mean relative humidity, mean water temperature, maximum wave height, mean wave period and maximum wave period. the shipments of swimming crab increases as mean wind velocity, mean atmospheric pressure, mean relative humidity, mean water temperature increases or mean wave period increase. However, as maximum wave height, maximum wave period decreases, the shipment of swimming crab increases.

Characteristics on the response of the stern trawler according to the state of its operation (선미트롤어선의 운항 형태에 따른 거동 특성)

  • PARK, Chi-Wan;KIM, Jong-Wha;KIM, Hyong-Seok;KANG, Il-Kwon
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.52 no.4
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    • pp.339-346
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    • 2016
  • The aim of this research was to the experimental data using statistical and spectral analyzing method to get the motion reponses of a stern trawler in operation states such as drifting, sailing and trawling according to the wave height. In drifting, the significant and the maximum valuer of roll in beam sea increased according to the wave height, but those of pitch decreased. The response and the period of peak of roll in beam sea were increased, but those of pitch decreased. In navigation, the significant and maximum values of roll increased remarkably according to the wave height, but those of pitch changed a little. The response of roll was highest in quartering sea, beam sea and then following sea, but those of pitch was highest in bow sea, head sea and then beam sea in the order of all wave heights. The period of peak of roll due to the wave height and the wave direction changed from 3.8 to 9.9 seconds, and those of pitch changed from 3.3 to 10.4 seconds. In trawling, the significant and maximum values of roll increased a little according to the wave height, but those of pitch increased significantly. The response of roll was highest in beam sea, bow sea and then quartering sea, but those of pitch was highest in head sea, following sea, and then beam sea in the order. The period of peak of roll due to the wave height and the direction changed from 6.6 to 10.9 seconds, and those of pitch changed from 6.7 to 11.2 seconds.

Evaluation of Wave Characteristics and JONSWAP Spectrum Model in the Northeastern Jeju Island on Fall and Winter (제주도 북동부 연안에서 추동계 파랑특성과 JONSWAP 스펙트럼의 적용성 평가)

  • Kang, Dong-Hyub;Lee, Byung-Gul
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.2
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    • pp.63-69
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    • 2014
  • Analysis frequency spectrum through observed wave data in northeastern shore, jeju island, during winter and fall, and review wave characteristics. In order to compute maximum wave height, we calculate the ratio of significant wave height to maximum wave height using the linear regression equation. In addition, for calculating JONSWAP spectrum, we assumed ${\gamma}$ value using significant wave height and peak frequency in the observation area. Consequently, the highest frequency is below 1 m in the case of significant wave height and during the first observation, the mean of height was estimated at 0.523 m and during the scend observation, it was 0.423 m. Furthermore, in peak frequency, the highest frequency was 0.12 Hz~0.15 Hz (period is nearly 6.67s~8.33s), the results of ${\gamma}$ from using significant wave height and peak frequency is 2.72 and the significant wave height calculated by straight linear regression equation was $1.635H_s$.

A Study of Statistical Properties of Waves in the Sea Area of Pohang (포항해역에서의 파랑의 통계적 특성에 대한 연구)

  • 안용호;김도영
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.05a
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    • pp.216-221
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    • 2001
  • In this paper, statistical properties of waves in the sea area of Pohang, Korea are examined absed on 1998-1999's wave data from directional wave buoy which is located Pohang(Janggigog). Wave data aquisition rate, monthly maximium, minimum and mean wave heights, frequency of wave direction are summarized. Wave height and period scatter diagrams and n-year return period wave heights are estimated. Wave periods of maximum wave heights are also estimated.

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