• 제목, 요약, 키워드: Korean Wave

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한국 연안의 극히 파랑환경과 Freak Wave의 특성에 관한 연구 (Extreme and Freak Wave Characteristics in the Coastal Writers of Korean Peninsula)

  • 류청로;윤홍주
    • Journal of Environmental Science International
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    • v.2 no.3
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    • pp.235-243
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    • 1993
  • Extreme environments and freak wave characteristics in the coastal waters of Korean Peninsula are analyzed using the observed wave data. Freak wave has been intensely emphasized as an important environmental force parameter in several recent research works. However, the mechanism and occurrence probability of freak wave are not clarified. The aims of this study we: to summarize the distribution of extreme environment for wind waves, and to find occurrence probability of freak wave in the coastal waters of Korean Peninsula. These extreme sea conditions are discussed by applying extreme value analysis method, and the statistic characteristics are summarized which can be used to the design and analysis of coastal structures. The mechanism and the occurrence probability of freak wave are also discussed in detail using wave parameters in considered with wave deformation in the coastal waters. Key Words : extreme wave, freak wave, extreme analysis, design wave, probability density.

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대진폭 해양파의 특성에 대한 연구 (A Study on the Characteristics of Large Amplitude Ocean Waves)

  • 김도영
    • 한국해양환경ㆍ에너지학회지
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    • v.12 no.2
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    • pp.61-67
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    • 2009
  • 이 논문에서는 freak wave가 포함된 시계열 파랑자료를 분석하였다. freak wave가 포함된 자료와 포함되지 않은 자료에 대하여 여러 가지 파랑 특성을 비교하였다. 파랑 자료는 Yura 해역에서 24시간 연속으로 측정된 자료를 분석하였고, 그 중에서 freak wave가 발생한 30분 동안 파랑과 인접한 30분간의 파랑자료를 집중적으로 분석하였다. 최대파의 파주기가 가장 긴 주기가 아닌 것을 볼 수 있다. 최대파의 파주기는 평균파주기보다 약간 길며, 유의파의 파주기보다는 짧은 것을 볼 수 있었다. 비록 해상 상태는 높지만, 레일리분포로 파고의 확률분포를 잘 표시할 수 있었다. Freak wave의 발생 전후의 파랑자료를 비교해 보면, 파랑스펙트럼의 특성은 큰 차이를 보이지 않으며, 발생한 경우에 비선형성이 증가한 것을 볼 수 있다. 그리고 freak wave 발생 직 후에 오히려 유의파고의 크기가 크게 나타났다. 따라서 유의 파고가 높은 것이 항상 freak wave의 발생확률을 높이지는 않는 것을 볼 수 있다.

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지반 강성구조 평가를 위한 러브파와 레일리파의 동시역산해석 (Joint inversion of Love Wave and Rayleigh Wave for Evaluating the Subsurface Stiffness Structure)

  • 조성호;이일화
    • 한국지반공학회:학술대회논문집
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    • pp.302-307
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    • 2005
  • Love wave and Rayleigh wave are the major elastic waves belonging to the category of the surface wave. The fact that Love wave is not contaminated by P-wave which makes Love wave superior to Rayleigh wave and other body waves. Therefore, the information that Love wave carries is more distinct and clearer than the information of Rayleigh wave. Based on theoretical research, the joint inversion analysis which is used both Love wave dispersion information and Rayleigh wave dispersion information was proposed. Purpose of the joint inversion analysis is to improve accuracy and convergency of inversion results utilizing that frequency contribution of each wave is different. This analysis technique is consisted of the forward modeling using transfer matrix, the sensitivity matrix determined to the ground system and DLSS(Damped Least Square Solution) as a inversion technique. The application of this analysis was examined through the field test.

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저가형 해파 모니터링 시스템을 위한 파형 모델링 (Wave Modeling for Low-cost Wave Monitoring System)

  • 이중현;이동욱;허문범
    • 전기학회논문지
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    • v.63 no.3
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    • pp.383-388
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    • 2014
  • This paper describes a wave modeling method using low-cost sensors. Wave modeling is applied to the wave monitoring system for accurate measurement of ocean wave parameters. The observation of ocean wave parameters is necessary to improve the accuracy of forecast of ocean wave condition. However, the ocean wave parameters measured by a low-cost wave monitoring system suffer from several errors. Therefore we introduce a wave modeling method to compensate the ocean wave parameters corrupted by errors. The proposed method is analyzed using experiments within controlled environment. It is verified that the accuracy of low-cost wave monitoring system can be increased by the proposed method.

CFD를 이용한 부양식 파력발전 장치의 성능해석 (Performance Analysis of Floating Wave Energy Converter by Using CFD)

  • 최용석;임태우;김유택
    • 수산해양교육연구
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    • v.27 no.5
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    • pp.1303-1309
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    • 2015
  • The behavior and flow characteristics of the floating wave energy converter were analyzed by using CFD in this study. The average significant wave height was confirmed as 0.5~2.0m from the Korean coastal sea area. This study was carried out by selecting a range of 1.0~1.6m in the wave height to simulate the operations of realistic wave energy converter system. The principle of a piston wave maker was applied in order to produce periodic wave. The behavior of the wave energy converter and the state of the wave overtopping according to the generated periodic wave were confirmed through the unsteady three-dimensional flow analysis. It was found that the wave overtopping rate according to the generated periodic wave was in range of the 11.6~30.0 kg/s.

Characteristics of wave propagation in a sloping-wall-type wave absorber

  • Zhu, Lixin;Lim, Hee Chang
    • 한국마린엔지니어링학회지
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    • v.39 no.8
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    • pp.843-848
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    • 2015
  • The objective of this study is to observe and optimize a typical ocean environment and reduce wave reflections in the wave flume. In order to generate ocean waves in the wave flume, a combination of a horizontal piston type wave generator and wave absorbers was installed in the channel. Two probes for measuring the wave heights, i.e., wave level gauges, were used to record the continuous variation of the wave surface, the phase difference, and the maximum (crest) and minimum (trough) points of the propagating waves. In order to optimize the shape and size of the propagating waves, several absorption methods were proposed. Apart from an active wave absorption method, we used methods that involved vertical porous plates, horizontal punching plates, and sloping-wall-type wave absorbers. To obtain the best propagating waves, a sloping-wall-type wave absorber was chosen and tested in terms of the constitutive filling materials and the location and shape of the plate. This study also focused on the theoretical prediction of the wave surface, separating them into the incident and reflective components. From the results, it is evident that the wave absorber comprising a hard filling material exhibits a better performance than the absorber comprising a soft material, i.e., the wave absorber can be a strong sink to control the energy of the incoming wave. In addition, larger wave absorbers correspond to lower reflectance because a larger volume can reduce the incoming wave energy. Therefore, at constant absorber conditions, the reflectance of the wave increases as the wave period increases. Finally, the reflectance of the wave was controlled to be less than 0.1 in this study so that the wave flume can be used to simulate an offshore environment.

음악요법의 한의학적 활용을 위한 신뢰도 및 적용 가능성 연구 (A Study on Reliability and Applicability of Oriental Medical Music Therapy Using)

  • 송민선;최찬헌
    • 동의생리병리학회지
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    • v.28 no.6
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    • pp.674-682
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    • 2014
  • The purpose of this study was to identify the effect of applying oriental music therapy and reliability of electroencephalogram(EEG) equipment. The study was approved by the critical trial judge committee from ${\bigcirc}{\bigcirc}$(IRB No. 2013-07) university. In order to measure test-retest reliability for 15 subjects, EEG for same participants were measured using same method mentioned above after 2 hours from the first measurement. Same provider implemented to each person at same time. Firstly, EEG was measured for 5 minutes after the subject with attached electrodes sat on chair comfortably for 10 minutes. Then, the subject was given mental stress using the four fundamental arithmetic operations for 5 minutes, and measured EEG for another 5 minutes. After that the subject sat on the chair comfortably listening oriental medicine music therapy for 5 minutes, and EEG was measured for 5 minutes again. There was no side effect regarding music therapy reported. Raw data, which was measured in each step, were converted through FFT(fast fourier transform) and analyzed after divided into certain frequency including ${\alpha}$ wave, ${\beta}$ wave, ${\theta}$ wave, immersion wave, stabilization wave, sef100 wave, and sef95 wave. Data were analyzed using wilcoxon signed rank test, Intraclass correlation coefficient(ICC), repeated measures ANOVA with the SPSS program. In test-retes method, there were significantly differences in ${\alpha}$ wave, ${\beta}$ wave, immersion wave, stability wave, ${\theta}$ wave, sef100 wave, sef95 wave. ICC has shown a high degree of reliability that it was ${\alpha}$ wave .877, ${\beta}$ wave .855, ${\gamma}$ wave .895, immersion wave .897, stability wave .816, ${\theta}$ wave .904, sef100 wave .910, sef95 wave .776. Also, there was a statistically significant difference in ${\alpha}$ wave after applying oriental music therapy. Based on these results, it is considered that average of the channel EEG and application of oriental music therapy would be practiced by increase of sample size using this machine.

A Numerical Study on Pontoon Type Floating Breakwaters in Oblique Waves

  • Kim, Do-Young
    • International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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    • v.3 no.1
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    • pp.23-28
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    • 2000
  • A numerical investigation was made to examine characteristics of rectangular pontoon type floating breakwaters in oblique waves. Sway and heave wave exciting forces, roll moment acting on the floating breakwater and three motion reponses decrease as the incident wave angle increases for the most of the wave ranges. There exists a minimum wave transmission coefficient which is a function of wave frequency. In short wave range wave transmission coefficient increases as the incident wave angle increases. In long wave range, however, wave transmission coefficient decreases as the wave incident angle increases.

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파랑에너지 해석 및 가용량 평가 연구 (Estimation of Wave Power in Korean Coastal Waters)

  • 김현주;최학선;김선경
    • 한국해양공학회지
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    • v.12 no.1
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    • pp.107-112
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    • 1998
  • The purpose of this study is to analyze the amount of available wave power and its characteristics related to the development of apractical system for ocean wave energy conversion in Korean coastal waters. The analysis method of wave power was established through comparison between theory and numerical simulation of deep sea wave by Inverse Fourier Transform with random phase method. Based on the results of comparison, wave power was estimated by use of data set from observed offshore and coastal waves and hindasted deep sea waves around the Korean peninsula. Annual mean wave power is estimated as about 1.8 ~ 7.0 kW for every metre of wave frontage at East sea, 1.5~5.3 kW at South sea and 1.0 ~ 4.1 kW at West sea, respectively. Mean wave power along deep sea front of coastal waters of Korea amounts to about 4.7 GW. Regional distribution and seasonal variation of wave power were discussed to develop practical utilization system of wave power of not so high grade of available wave power.

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심해파의 불안정성에 관한 실험 연구 -제2부 : 초기변형파의 불안정성 (Experimental Study of Deep-Water Wave Instability : Part 2. Evolution of The Initially-Modulated Wave Train)

  • 조원철
    • 대한토목학회논문집
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    • v.13 no.1
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    • pp.203-211
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    • 1993
  • 초기 변형파(파고 또는 주파수에의 변형)의 실험이 파랑의 전개에 있어 초기 변형의 영향을 살펴보기 위해 행하여졌으며, 이로부터 초기 변형파의 파고와 주파수의 변형이 정상파의 전개에 있어서 보다 더 크고 빨리 일어남이 관찰되었다. 그러나 작은 파형경사를 가진 초기 파고변형파의 전개에 있어서는 초기에서 중기까지는 파랑의 파고와 주파수의 변형이 빠르게 일어남이 관찰되었으나 말기에는 이 변형파의 최초의 형태나 주파수로 다시 전환됨이 관찰되었다.

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