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

<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/m². 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>

Quantification of Measurement and Model Effects in Monopile Foundation Scour Protection Experiments

The present work introduces an analysis of the measurement and model effects that exist in monopile scour protection experiments with repeated small scale tests. The damage erosion is calculated using the three dimensional global damage number S3D and subarea damage number S3D,i. Results show that the standard deviation of the global damage number σ(S3D)=0.257 and is approximately 20% of the mean S3D, and the standard deviation of the subarea damage number σ(S3D,i)=0.42 which can be up to 33% of the mean S3D. The irreproducible maximum wave height, chaotic flow field and non-repeatable armour layer construction are regarded as the main reasons for the occurrence of strong model effects. The measurement effects are limited to σ(S3D)=0.039 and σ(S3D,i)=0.083, which are minor compared to the model effects.

PEMBANGKIT LISTRIK TENAGA GELOMBANG LAUT DENGAN MENGGUNAKAN TEKNOLOGI OSCILATING WATER COLUMN (OWC) DI PERAIRAN MARANA

The alternatives to overcome electricity shortage in Indonesia is wave generating. One of the methods conducted in this research is OWC (Oscilating Water Column) based on study area criteria (Marana Village). OWC method can convert ocean wave energy atwave columnoscillationto generate electricity. To be able to produce electricity, this OWC device will train the wave energy through the OWC door hole. This research determine the amount of waves that can be utilized in Marana waters to be converted into units of electricity (watts). The amount of wave height that can be used, depends on the amount of wind that is in the waters of Marana. In addition to wave height, tidal is also needed to know the placement of Oscilating Water Column (OWC) is so that when the tidal water occurs, OWC is still in the condition of the wave. In addition, the bathymetry of the sea is also needed to know at the depth of how placed this OWC. Based on the results obtained from wave forecasting using the 2002-2006 wind data obtained maximum wave height for 5 years is 0.204 m in Year 2003. Which can generate electricity of 0.688 watts. Where from concluded in Marana waters do not have the potential to build Sea Wave Power Plant.

Experiments on initial stages of development of dam-break waves

ABSTRACT The initial stages of instantaneous dam-break waves are here evaluated spatially and temporally through 36 physical experiments. Different conditions were tested for downstream (J) and upstream (M) water depths and their ratios (r) to approach realistic conditions for prototype dams. Two non-dimensional parameters are proposed – effective height (HEF) and effective velocity (VEF) – to evaluate water depths and velocity peaks along the dam-break wave evolution. The maximum wave height is estimated as a function of r, whereas the HEF is inversely related to r. The maximum VEF peak is registered for r between 0.1 and 0.2, considered a critical description for real dams. The presence of downstream water depth also modifies the dam-break wave frontal shape and types of wave break features. Previously published classifications of the moving wave based on those features are now expanded with a first tested r = 0.8 in which no jet was identified (undulated movement).

New Weighted Total Acceleration on Momentum Euler Equation for Formulating Water Wave Dispersion Equation

In this present study, weighted total acceleration for Kinematic Free Surface Boundary Condition (KFSBC) and in momentum Euler equation was formulated. Furthermore, by using both aforementioned equations, the nonlinear water wave dispersion equation was then formulated. The wavelength obtained from dispersion equation is determined by weighting coefficient. The weighting coefficient value was determined by using the maximum wave height and critical wave steepness criteria which have been obtained from the previous studies.

REPRODUCTION ANALYSIS OF HUMAN DRIFTING BEHAVIOR DURING TSUNAMI USING NUMERICAL CALCULATION

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