EXPERIMENTAL STUDY ON BEHAVIOR OF NON-LINEARITY AND OCCURRENCE OF MAXIMUM WAVE HEIGHT ON SLOPE

2020 ◽  
Vol 76 (2) ◽  
pp. I_43-I_48
Author(s):  
Hiroaki KASHIMA ◽  
Nobuhito MORI
Keyword(s):  
Experimental Study ◽  
Wave Height ◽  
Maximum Wave Height

scholarly journals LABORATORY SIMULATIONS OF WAVE ATTENUATION BY AN EMERGENT VEGETATION OF ARTIFICIAL PHRAGMITES AUSTRALIS: AN EXPERIMENTAL STUDY OF AN OPEN-CHANNEL WAVE FLUME

2015 ◽  
Vol 23 (4) ◽  
pp. 251-266 ◽  
Author(s):  
Li YIPING ◽  
Desmond Ofosu ANIM ◽  
Ying WANG ◽  
Chunyang TANG ◽  
Wei DU ◽  
...  
Keyword(s):  
Experimental Study ◽  
Phragmites Australis ◽  
Wave Height ◽  
Plant Density ◽  
Wave Attenuation ◽  
Emergent Vegetation ◽  
Irregular Waves ◽  
Shore Protection ◽  
Near Shore ◽  
Wave Conditions

This paper presents a well-controlled laboratory experimental study to evaluate wave attenuation by artificial emergent plants (Phragmites australis) under different wave conditions and plant stem densities. Results showed substantial wave damping under investigated regular and irregular wave conditions and also the different rates of wave height and within canopy wave-induced flows as they travelled through the vegetated field under all tested conditions. The wave height decreased by 6%–25% at the insertion of the vegetation field and towards the downstream at a mean of 0.2 cm and 0.32 cm for regular and irregular waves respectively. The significant wave height along the vegetation field ranged from 0.89–1.76 cm and 0.8–1.28 cm with time mean height of 1.38 cm and 1.11 cm respectively for regular and irregular waves. This patterns as affected by plant density and also location from the leading edge of vegetation is investigated in the study. The wave energy attenuated by plant induced friction was predicted in terms of energy dissipation factor (fe) by Nielsen’s (1992) empirical model. Shear stress as a driving force of particle resuspension and the implication of the wave attenuation on near shore protection from erosion and sedimentation was discussed. The results and findings in this study will advance our understanding of wave attenuation by an emergent vegetation of Phragmites australis, in water system engineering like near shore and bank protection and restoration projects and also be employed for management purposes to reduce resuspension and erosion in shallow lakes.

Searching for Factors that Limit Observed Extreme Maximum Wave Height Distributions in the North Sea

2008 ◽  
pp. 127-138 ◽  
Author(s):  
Gerrit Burgers ◽  
Frits Koek ◽  
Hans de Vries ◽  
Martin Stam
Keyword(s):  
Wave Height ◽  
North Sea ◽  
Maximum Wave Height ◽  
The North ◽  
The North Sea

scholarly journals REPRODUCTION ANALYSIS OF HUMAN DRIFTING BEHAVIOR DURING TSUNAMI USING NUMERICAL CALCULATION

2020 ◽  
pp. 34
Author(s):  
Riko Morita ◽  
Taro Arikawa
Keyword(s):  
Numerical Calculation ◽  
Wave Height ◽  
Prediction Method ◽  
Great East Japan Earthquake ◽  
Numerical Calculations ◽  
Water Tank ◽  
Maximum Wave Height ◽  
Hydraulic Experiment ◽  
Secondary Damage ◽  
Simulation Results

Along with the 2011 Great East Japan Earthquake (Mw 9.0), a huge tsunami exceeding a maximum wave height of 15 m occurred. Many people and objects were destroyed and drifted by the tsunami. In addition, these debris were transported to various places that could not be predicted, resulting in significant secondary damage and increase in the number of missing. Therefore, in order to reduce the amount of damage, it is important to predict the behavior and landing points of person after set adrift in a tsunami. The best way to increase the rescue rate is to predict in advance the area that people will be drifted, and prioritize searching operations at that area. Although there has been considerable number of studies which handle the drifting behavior of containers and ships (e.g., Kaida et al., 2016), the prediction of drifting areas focusing on people has not been conducted. Moreover, a drifting area prediction method has not yet been established. The purpose of this study is to conduct a hydraulic experiment using a flat water tank, and observe the drifting area of the drifting object. Then, we conducted numerical calculations and compared simulation results with the experimental ones.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/1yhKuodhCbg

scholarly journals Pemanfaatan Data Angin Untuk Karakteristik Gelombang Laut Di Perairan Natuna Berdasarkan Data Angin tahun 2009 - 2018

2019 ◽  
Vol 8 (2) ◽  
pp. 55
Author(s):  
Ary Afriady ◽  
Tasdik Mustika Alam ◽  
Mochamad Furqon Mustika Azis Ismail
Keyword(s):  
Wave Height ◽  
Wave Period ◽  
Wind Data ◽  
Wave Direction ◽  
The West ◽  
Maximum Wave Height ◽  
Transition Season ◽  
Forecasting Analysis ◽  
Environmental Prediction ◽  
Wave Forecasting

Analisis data angin dilakukan untuk meramalkan dan menentukan karakteristik gelombang laut di perairan Pulau Natuna. Data angin yang digunakan dalam penelitian ini berasal dari National Centers for Environmental Prediction (NCEP) selama 10 tahun dari tahun 2009 sampai dengan tahun 2018. Metoda yang digunakan untuk estimasi tinggi, periode dan arah gelombang laut yang dibangkitkan oleh angin adalah metode Svedrup, Munk dan Bretschneider (SMB). Hasil perhitungan peramalan karakteristik gelombang diperoleh bahwa pembentukan gelombang didominasi oleh arah yang berasal dari timur laut dan terjadi pada musim barat dan musim peralihan 1. Adapun pada musim timur dan peralihan, arah dominan gelombang masing-masing berasal dari selatan dan barat daya. Tinggi gelombang maksimum 1,0-1,4 m sering terjadi pada musim musim timur, adapun tinggi gelombang minimum 0,2-0,6 m dominan terjadi pada musim musim peralihan. Periode gelombang dominan ditemukan pada kisaran 7-9 detik yang terjadi pada tiap musim.  The analysis of wind data has been done to forecast and determine the characteristic of the ocean wave in Natuna Island waters. The wind data in this study came from the National Centers for Environmental Prediction (NCEP) for a period of 10 years from 2009 to 2018. The method to estimate wave height, wave period, and wave direction generated by wind is Sverdrup, Munk dan Bretschneider (SMB) system. The results of wave forecasting analysis show that the formation of the wave is mainly originated from the northeast which occurs during the west and first transition season. As for the east and second transition season, the origin of wave formation coming from the south and southwest, respectively. The maximum wave height of 1.0-1.4 m frequently occurs during the east monsoon, while the minimum wave height. The dominant wave period is found in the range of 7-9 seconds, which occurs in every season. 

scholarly journals NEW WAVE PRESSURE FORMULAE FOR COMPOSITE BREAKWATERS

1974 ◽  
Vol 1 (14) ◽  
pp. 100 ◽  
Author(s):  
Yoshimi Goda
Keyword(s):  
Wave Height ◽  
Wave Action ◽  
Smooth Transition ◽  
New Wave ◽  
Wave Pressure ◽  
Maximum Wave Height ◽  
Design Wave Height

A proposal is made for new wave pressure formulae, which can be applied for the whole ranges of wave action from nonbreaking to postbreaking waves with smooth transition between them. The design wave height is specified as the maximum wave height possible at the site of breakwater. The new formulae as well as the existing formulae of Hiroi, Sainflou, and Minikin have been calibrated with the cases of 21 slidings and 13 nonslidings of the upright sections of prototype breakwaters. The calibration establishes that the new formulae are the most accurate ones.

The Equivalent Power Storm Model for Long-Term Predictions of Extreme Wave Events

2009 ◽  
Author(s):  
Francesco Fedele ◽  
Felice Arena
Keyword(s):  
Wave Height ◽  
Return Period ◽  
Shape Parameter ◽  
Extreme Wave ◽  
Maximum Wave Height ◽  
Wave Measurements ◽  
Sea Storm ◽  
Storm Model ◽  
Good Agreement

We present the Equivalent Power Storm (EPS) model as a generalization of the Equivalent Triangular Storm (ETS) model of Boccotti for the long-term statistics of extreme wave events. In the EPS model, each actual storm is modeled in time t by a power law ∼|t−t0|λ, where λ is a shape parameter and t0 is the time when the storm peak occurs. We then derive the general expression of the return period R(Hs > h) of a sea storm in which the maximum significant wave height Hs exceeds a fixed threshold h as function of λ. Further, given the largest wave height Hmax, we identify the most probable storm in which the largest wave occurs and derive an explicit expression for the return period R(Hmax >H) of a storm in which the maximum wave height exceeds a given threshold H. Finally, we analyze wave measurements retrieved from two of the NOAA-NODC buoys in the Atlantic and Pacific oceans and find that the EPS predictions are in good agreement with those from the ETS model.

scholarly journals Kajian Energi Gelombang Laut Di Daerah Abrasi Serangai, Bengkulu Utara Melalui Pengamatan Tinggi Gelombang Laut

2021 ◽  
Vol 11 (2) ◽  
pp. 143
Author(s):  
Ashar Muda Lubis ◽  
Yosi Apriani Putri ◽  
Rio Saputra ◽  
Juhendi Sinaga ◽  
M Hasanudin ◽  
...  
Keyword(s):  
Wave Height ◽  
Wave Energy ◽  
Seasonal Variations ◽  
Coastal Area ◽  
Significant Wave Height ◽  
Ocean Waves ◽  
Wave Period ◽  
Maximum Wave Height ◽  
Significant Wave ◽  
Sea Wave

<p class="AbstractText"><span lang="EN-AU">The Serangai area, Batik Nau District, North Bengkulu has the highest average abrasion speed of 20 m/year. The abrasion could cause the coastal area to erode the coastline till several tens of meters. The purpose of this study was to determine the height of the ocean waves and to determine the energy of the ocean waves that has the potential to accelerate the abrasion process in the Serangai area. The research was carried out on November 5-7, 2018 in the Serangai beach area at a depth of 5 m using SBE 26 Plus Seagauge Wave equipment. The results showed that the observed wave height was between 0.8-1.6 m with a significant wave height (Hs) of 1.38 m. In addition, the wave period ranges from 5-11 s with a significant wave period (Ts) of 8.2 s. The result also shows that the maximum wave height of 1.6 m occurred on November 7, 2018 with maximum wave energy of 1800 J/m<sup>2</sup>. This result can perhaps accelerate the abrasion process in the Serangai area. It can also be seen that the wave height in the Serangai region is higher than in several other areas in Indonesia. However, it is necessary to continue observing the wave height to see the seasonal variations in sea wave height in Serangai area.</span></p>

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