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Journal : REKAYASA

Pengaruh Konfigurasi Terumbu Buatan Bentuk Heksagonal pada Kemampuan Peredaman Gelombang Wirayuhanto, Harish; Armono, Haryo Dwito
Rekayasa Vol 14, No 1: April 2021
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v14i1.10042

Abstract

An artificial reef is a structure that is placed underwater and functions as a natural coral reef. Apart from being an artificial reef, the function of artificial reefs is also as a submerged breakwater. As a breakwater, it is necessary to know the level of effectiveness in reducing waves and the impact of scouring arising from the laying of artificial reef structures. This research was conducted to determine the correlation between the ability of wave attenuation to the depth of scouring due to variations in laying (structure gap distance) and variations in waves on artificial reefs in hexagonal shape with a scale model of 1:10. From the results of research conducted at the Marine Energy Laboratory of the Department of Marine Engineering, FTK ITS obtained, for laying structures with a gap of 1D, they have better wave attenuation capabilities with a small maximum scouring depth, namely with a Kt value of 0.844 and a scouring depth of 3 cm. For the laying of the structure with a distance of 0D, it has a greater value of transmission coefficient (Kt), which is 0.911 with a greater value of the maximum scouring depth, which is 3.5 cm.
Efek Koefisien Transmisi akibat Variasi Wave Stepness pada Hexagonal Artificial Reef Wirayuhanto, Harish; Armono, Haryo Dwito; Ridlwan, Asfafur; Febrianto, Try
Rekayasa Vol 14, No 3: Desember 2021
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v14i3.12485

Abstract

Waves that move towards the coast have an energy level that corresponds to the magnitude of the generating force. Waves with high energy intensity are dominantly destructive when they hit the coastal area. In order to reduce the destructive effect of waves, coastal protection structures are needed to dampen the wave energy. Artificial coral reef (artificial reef) is one type of structure that can reduce wave energy. Besides functioning as an artificial reef for marine ecosystem biota, but also as a submerged breakwater structure. This study was conducted to determine the relationship between wave stepness and the transmission coefficient produced by hexagonal artificial reefs with a model scale of 1:10. The test is carried out using regular waves with a range of H/gT2 values between 0.0007 – 0.006. The results of research conducted at the Marine Energy Laboratory of the Department of Marine Engineering, FTK ITS, show that an increase in the value of wave steepness correlates with an increase in the value of the transmission coefficient (Kt) for all tests and configurations. The 1D structure configuration has a lower transmission coefficient (Kt) than the 0D structure configuration for each variation of the test wave.
Pengaruh Tinggi Puncak Struktur Hexagonal Artificial Reef Terhadap Kemampuan Redamanan Gelombang Muhammad Baharudin Fahmi; Haryo Dwito Armono; Muhammad Zikra; Harish Wirayuhanto
Rekayasa Vol 15, No 2: Agustus 2022
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v15i2.14848

Abstract

Generally, the purpose of artificial reefs is to rebuild naturally occurring coral reefs that have been destroyed. Without sacrificing the attractiveness of the protected beach, these manmade reefs functioned as new habitats for marine life and protected coasts by reducing wave energy. on the other side man-made artificial reefs can perform as submerged breakwaters, their ability to dampen incoming waves must be investigated. In this paper, the researchers present a new shape in the form of a hexagonal artificial reef. The wave attenuation performance index is calculated using the wave attenuation performance rating. The research focuses on the effect of structural height (h/d) on transmission wave value using a physical testing method on a scale of 1:10 at the wave flume of the Department of Marine Engineering, Sepuluh Nopember Institute of Technology, Surabaya. The test results indicate that the smallest transmission coefficient (KT) was produced on artificial reefs Configuration A-3 with the greatest submerged depth (h/d=0.75). The parameter results indicate that the greater the wave steepness (H/gT2) and the significantly larger the immersion depth (h/d), the better the wave reduction.
Pemodelan Pola Transport Sedimen di Perairan Desa Berakit dan Pengudang Kabupaten Bintan Rahma Sarita; Mario Putra Suhana; Harish Wirayuhanto
Rekayasa Vol 16, No 1: April 2023
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v16i1.18386

Abstract

Sedimentation and erosion processes can be influenced by hydro-oceanographic factors. These factors include waves, currents, and tides because they interact directly with the coastal/coastal area. Related to these problems, sedimentation and erosion is one thing that needs to be studied. One way that is used in providing information about these that is widely used is to use a hydrodynamic model. Based on this, it can be seen that it is important to conduct research to determine sediment properties such as the type and type of sediment with sediment transportt modeling in Berakit and Pengudang villages. This research was carried out using the MIKE21 Software hydrodynamic modeling for one month in June 2021 using hydrodynamic modeling, the Flow Model FM Sand Transportt module. Sediment transportt observed is bottom sediment or bed load. The research results are shown in 4 conditions, namely towards high tide, highest tide, towards low tide and lowest tide. Sediment transportt at high tide with erosion of -0.10 and sedimentation of 0.25 m/day and at the highest tide shows an erosion value of -0.24 and sedimentation of 0.32 m/day. Sediment transportt towards low tide with erosion of -0.15 and sedimentation of 0.20 m/day and at the lowest ebb erosion occurs with a value of -0.36 and sedimentation of 0.20 m/day.
Pemodelan Hidrodinamika 2-Dimensi Arus Laut Permukaan Perairan Desa Berakit Kabupaten Bintan Nur Anisa; Mario Putra Suhana; Harish Wirayuhanto
Rekayasa Vol 16, No 2: Agustus 2023
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v16i2.17227

Abstract

Information related to ocean currents is not yet available in Berakit Village waters, ocean currents are an important parameter to determine the condition of a waters. An alternative that can be used to determine the condition of ocean currents is to use hydrodynamic modeling. The purpose of the study was to analyze the distribution pattern and characteristics of surface ocean currents. This research was conducted by conducting 2-dimensional hydrodynamic modeling simulating ocean currents for 1 (one) year in December 2020-November 2021 using MIKE 21 software by sampling in 6 (six) different conditions, namely at the highest tide, lowest tide, high tide. towards the ebb and flow of the full moon, the ebb towards the negligible tide, the tide towards the ebb tide and the ebb towards the negligible tide. The model results were validated by the RMSE formula with a value of 2%, the model results were very good, so that they could be used as a reference in providing an overview of the real conditions of the pattern and current distribution at the research location. The movement of ocean currents at the time of the full moon and negligible dominant currents move towards the south of the waters, while at the time of the full tide and negligible the dominant currents move towards the north of the waters. In the north season, the current velocity ranges from 0.00006 m/s-0.125 m/s with the dominant movement towards the north. East monsoon currents move predominantly north and south with speeds ranging from 0.0000003 m/s-0.129 m/s. In the south monsoon the dominant current moves to the north and south at a speed of 0.0000007 m/s-0.13 m/s. in the west season, the dominant current moves to the north and south at a speed of 0.00001 m/s-0.12 m/s. The speed of the dominant ocean currents is greater at high tide compared to low tide, this is due to differences in sea level elevation in the opposite direction of motion. 
Analisis Kecenderungan Musiman Tinggi Gelombang Signifikan di Laut Indonesia Tahun 1980-2020 Untuk Mendukung Pembangunan Pesisir Berkelanjutan Fahmi, Muhammad Baharudin; Wirayuhanto, Harish; Dwito Armono, Haryo; Zikra, Muhammad; Lorentius, Suratno
Rekayasa Vol 18, No 2: Agustus, 2025
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v18i2.29978

Abstract

Sea level rise, as one of the consequences of global climate change, has significantly impacted oceanographic dynamics, particularly wave characteristics. One of the most critical affected parameters is significant wave height, which directly influences maritime safety, the sustainability of fisheries, the stability of coastal infrastructure, and the risk of coastal erosion and tidal flooding. As an archipelagic nation with the second-longest coastline in the world, Indonesia is highly vulnerable to such changes. Therefore, understanding the spatial and temporal trends in significant wave height is essential to support effective adaptation and mitigation policies in coastal regions. This study aims to analyze the trend of increasing significant wave height in Indonesian waters using ERA5 reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) over the period from 1980 to 2020. The trend analysis was conducted using non-parametric statistical methods, namely the Mann-Kendall test to detect statistically significant trends and Sen’s Slope Estimator to quantify the rate of change. A significance level of 0.05 was applied in the analysis. The results indicate a significant upward trend in significant wave height across several Indonesian maritime regions. Conversely, the northern waters of Central Java and the northern region of Masalembu Island exhibited no statistically significant trend across seasons. The Banda Sea and southern Papua experienced significant increases during the dry season (JJA) and the second transitional season (SON), with a peak rate of 1.70 cm/year. In the southern waters of Lombok Island, positive trends were observed in the wet season (DJF) and the first transitional season (MAM), with rates reaching 1.46 cm/year. The highest trend was recorded in the southern waters of Java during the wet season (DJF), at 1.72 cm/year. These findings suggest that most Indonesian waters are experiencing significant changes in wave characteristics as a result of climate change, highlighting the urgency for long-term oceanographic monitoring and the integration of wave data into coastal development and climate adaptation strategies.