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Gravity wave interaction with a wave attenuating system

APPLIED OCEAN RESEARCH 2020年 101卷 1页

作者： Vijay, K. G. Nishad, C. S. Neelamani, S. Sahoo, T. IIT Kharagpur Dept Ocean Engn & Naval Architecture Kharagpur 721302 W Bengal India Pandit Deendayal Petr Univ Sch Technol Dept Math Gandhinagar 382007 Gujarat India Kuwait Inst Sci Res Environm & Life Sci Res Ctr Coastal Management Program POB 24885 Safat 13109 Kuwait

In the present study, gravity wave interaction with a wave attenuating system (WAS) comprised of a series of surface piercing thin vertical porous plates fixed on a fully submerged rigid pontoon is analyzed. For the wave past porous barriers, a quadratic pressure drop is considered to account for the energy dissipation due to changes in wave steepness. A numerical model based on iterative multi-domain boundary element method is developed under the assumption of a small amplitude water wave theory. The scattering coefficients (reflection and transmission) and wave force coefficients (horizontal, vertical and moments) are computed for different wave and structural parameters such as the number of plates, relative plate width, the relative depth of submergence, plate porosities, and relative wave steepness. The results demonstrate that with the creation of trap zones through multiple porous plates on a submerged rigid pontoon, it is possible to reduce wave transmission by 60-70%. For optimum performance across all water depths, it is suggested for the WAS to have 1 < B/h < 1.5 and h1/h < 0.3. Also, interestingly there is a 25-30% reduction in the vertical wave forces which reduces the load acting on the ancillary equipment. The WAS is found to perform well for porosity mu = 20%, above which the wave transmission increases gradually. The study results can be useful in the cost-effective design of this type of special wave barrier for a range of coastal engineering field applications.

关键词： Wave attenuating system Thin porous barriers Linear and nonlinear pressure drop Multi-domain boundary element method

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Determination of methanol concentration in ethanol in liquid phase by a phononic crystal Mach-Zehnder interferometer

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PHYSICA SCRIPTA 2021年第12期96卷 125032-125032页

作者： Salman, Aysevil Ates, Emine Bicer, Ahmet Deniz, Sualp Cicek, Ahmet Korozlu, Nurettin Piri Reis Univ Dept Naval Architecture & Marine Engn Fac Engn TR-34940 Istanbul Turkey Burdur Mehmet Akif Ersoy Univ Fac Arts & Sci Dept Nanosci & Nanotechnol TR-15030 Burdur Turkey Burdur Mehmet Akif Ersoy Univ Golhisar Vocat Sch Hlth Serv Dept Opticianry TR-15400 Burdur Turkey Burdur Mehmet Akif Ersoy Univ Machine Program Dept Machinery & Met Technol Tech Sci Vocat Sch TR-15400 Burdur Turkey

A practical and portable ultrasonic interferometric sensor to detect methanol concentration in ethanol in the liquid phase is numerically investigated. For high-sensitivity operation, the sensor is designed as a Mach-Zehnder interferometer based on a linear-defect waveguide in a two-dimensional phononic crystal, which consists of square array of cylindrical steel rods in water. The waveguide core comprises polyethylene tubing, impedance-matched with water, filled with either pure ethanol or ethanol-methanol binary mixture, allowing fast replacement of the analyte. Band structure analyses through the finite-element method are carried out to obtain guiding modes at frequencies around 200 kHz. With 50 x 21 cells with 4.2 mm periodicity, the total sensor area is 210-by-88.2 millimeters, which can be significantly reduced by increasing the operating frequency to megahertz range. The interferometer is constructed via T junctions of the waveguide, which facilitates low-loss equal splitting and recollection of ultrasonic waves. Sample and reference wave paths are constructed by filling polyethylene tubing on the upper and lower halves of the interferometer with the ethanol-methanol mixture and pure ethanol, respectively. Frequency-domain finite-element method simulations reveal that the sensor output is characterized by several transmission peaks, one of which is centered at 203.35 kHz with a full-width at half-maximum of 20 Hz, resulting in a quality factor of 10167. The peak frequency of this peak redshifts at a rate of 7.24 Hz per percent volume fraction change in methanol. The peak shift is linear when the methanol volume fraction is below 10%. Besides, the interferometric sensor has a figure of merit around 0.35. The proposed ultrasonic sensor offers rapid detection of methanol content in ethanol with high sensitivity.

关键词： methanol ethanol liquid-phase ultrasonic sensor phononic crystal Mach-Zehnder interferometer

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Hull Design of Solar Powered Recreational Electric Boat for Indonesian Waters 3

Hull Design of Solar Powered Recreational Electric Boat for ...

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3rd International Tropical Renewable Energy Conference on Sustainable Development of Tropical Renewable Energy (i-TREC)

作者： Sunaryo, Sunaryo Yusro, Fahmi Univ Indonesia Mech Engn Dept Naval Architecture & Marine Engn Study Program Depok 16424 Indonesia

Indonesia with its more than 17,000 islands and its geographical location as tropical country is blessed with many marine tourism destinations such as beautiful beaches and coral reefs, coastal community culture etc., in fact tourism is ranked as 3rd highest foreign income. On the other hand Indonesian government is also committed to promote the use of environmentally friendly new and renewable energy as an alternative to the fossil fuel which highly contribute to the air pollution. In conjunction with government's program in developing the marine tourism and in using green energy, the research is aimed to design solar powered recreational boat for tourism in Indonesia. The paper is focused on the design of the boat structure such as the hull type, the environmental friendly material for the boat hull, the arrangement of the boat that would suitable to be powered with solar energy etc. For this purpose references are obtained from literature study, experts' opinion, and previous experiments.

关键词： Fossil fuels

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Electrical system design of solar powered electrical recreational boat for Indonesian waters 3

Electrical system design of solar powered electrical recreat...

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3rd International Tropical Renewable Energy Conference on Sustainable Development of Tropical Renewable Energy (i-TREC)

作者： Sunaryo, Sunaryo Ramadhani, Adri Wirawan Univ Indonesia Dept Mech Engn Naval Architecture & Marine Engn Study Program Depok 16424 Indonesia

Indonesia has more than 17,000 islands and has plenty of beautiful beaches and underwater spots which have great potential for maritime tourism. Tourism was ranked 3rd on Indonesia's foreign income and plays an important role for the country's ecomony. Despite having potential advantages, the government has not yet maximized its efforts to develop the attractiveness of its maritime tourism. Beside the beautiful spots Indonesia is also blessed with all year long sun shine, which could be tapped as renewable and green energy as substitution to fossil fuel. Refer to these great advantages of natural resources the research was aimed to support the government's program in developing its maritime tourism and to promote the use of green and renewable energy by designing a solar-powered tourism recreational boat which has 12 meters of length. The paper is focused on the design of solar energy and its electrical system, which includes conversion of solar energy to electrical energy and store it in the battery, the required electrical power is also predicted based on the appliances and equipment installed in the boat, the optimum attachment of solar panels on the boat structure is also calculated. All the methods and information we use are obtained from literature study, discussion with experts, and surveys to Jagur as solar-powered electric boat from Universitas Indonesia.

关键词： Solar energy

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Computational investigation into resistance characteristics of a full-scale pusher-barge system

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AIP Conference Proceedings 2022年第1期2543卷

作者： Ahmad Fitriadhy Nur Amira Adam Raja Noor Syaheeda Faisal Mahmuddin Suandar Baso Mohd Azlan Musa Anuar Abu Bakar Mohd Asamudin A. Rahman Mohd Hairil Mohd 1)Program of Naval Architecture Faculty of Ocean Engineering Technology and Informatics Universiti Malaysia Terengganu 21030 Kuala Terengganu Terengganu Malaysia 2)Program of Boat Making Technology Department of Mechanical Kolej Vokasional Pasir Gudang Johor Malaysia 3)Department of Marine Engineering Faculty of Engineering Hasanuddin University Jalan Poros Malino km. 6 Bontomarannu 92172 Gowa Sulawesi Selatan Indonesia 4)Department of Naval Architecture Faculty of Engineering Hasanuddin University Jalan Poros Malino km. 6 Bontomarannu 92172 Gowa Sulawesi Selatan Indonesia

In the presence of hydrodynamic motion interference between pusher and multiple barge configurations, a reliable investigation allowing an accurate prediction of her total resistance is obviously required. To achieve such objective, the Computational Fluid Dynamics (CFD) approach is then proposed to predict the total ship’s resistance of a pusher-barge system in the calm water condition. The various barge’s configurations incorporated with various Froude numbers (Fr) have been considered in the computational simulation incorporated with the full-scale dimension of the pusher-barge. In general, the CFO results revealed that the total resistances of the various configurations of the pusher-barge system had a qualitatively good agreement with the experimental model test results. Merely, the increase of Froude number (Fr=0.128 to 0.308) was proportional to the magnitude of total resistance. In addition, the pusher-barge system of the 33BP configuration provides the highest resistance as compared to others. It should be noted here that the pusher-barges configurations led to the susceptible effect to the total ship’s resistance which resulted in remarkable increase of the effective power values as the substituting their arrangements from the longitudinal configurations and to the lateral ones. This finding provides a very valuable insight aimed at selecting the proper pusher-barge configurations towards reducing the total ship’s resistance.

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Hydrodynamic characteristics and power generation performance investigation of resonance caisson WEC

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Ocean Engineering 2025年 337卷

作者： Wenbo Deng Jiawen Li Lunyu Zhang Jiawei Hao Jin Yan Ji Huang Naval Architecture and Shipping College Guangdong Ocean University Zhanjiang 524088 China Guangdong Provincial Key Laboratory of Intelligent Equipment for South China Sea Marin Ranching Guangdong Ocean University Zhanjiang 524088 China Doctoral Degree Program in Ocean Engineering Technology National Taiwan Ocean University Keelung 20224 Taiwan Technical Research Center for Ship Intelligence and Safety Engineering of Guangdong Province Zhanjiang 524005 China

Wave energy has attracted significant attention due to its wide distribution and pollution-free characteristics. Resonance caisson wave energy converter (RC-WEC) technology utilizes resonance principles to effectively enhance power generation efficiency. This study utilizes diffraction-radiation theory and the boundary element method to investigate the frequency domain hydrodynamic characteristics of RC-WEC. We evaluate operational performance using capture width spectra under varying caisson opening degree and wave incidence angles. The results indicate that the resonance caisson has a significant gain in energy conversion efficiency for the independent float. RC-WEC significantly improves hydrodynamic parameters(e.g., heave response amplitude) of the float. Smaller caisson opening degrees increase spectral peaks while narrowing bandwidth. Furthermore, we also observe an asymmetric capture width distribution across wave incidence angles ranging from 0 to 180°, with maximum values at 135°. In a comprehensive evaluation, RC-WEC improves the capture width by 78–94 % relative to the independent float, demonstrating that resonance caisson is effective in actively inducing resonance in the flow field to optimize the energy conversion capability of WEC. This paradigm shift from passive wave absorption to active resonance development emphasises an efficient way to improve the performance metrics of float-based WEC systems.

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Design and calculation of mechanical system for solar-powered electric boat 2

Design and calculation of mechanical system for solar-powere...

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2nd International Tropical Renewable Energy Conference (I-TREC)

作者： Sunaryo Nurachman, Dendi Imfianto, Pradhana S. Univ Indonesia Depok Dept Mech Engn Naval Architecture & Marine Engn Study Program Depok 16424 Indonesia

Indonesian government has a flagship program that is to promote the nation through the maritime sector and make Indonesia as Global Maritime Fulcrum. To achieve that, sea transportation is very important for the development of Indonesia. But sea transportation is also the highest contributor to the air pollution and global warming. In order to reduce the source of global warming Indonesian Government has a strategic plan to gradually replace the use of fossil energy with renewable energy. One of the renewable energy that can be used effectively in Indonesia is solar energy, because Indonesia located along the equator and has a high intensity of sunlight that means it has excellent solar energy availability. In attempt to contribute to the Government's energy strategic plan, the research is aimed to design a solar-powered electric boat with single pilot. The project is a further development of the solar boat created by the Universitas Indonesia team that participated in the International Solar-boat Challenge competition in the Netherlands. The paper is focused on the design and calculation of its mechanical system. The system is divided into propulsion system, steering system, and bilge pump system. The research is conducted based on literature study, discussion with experts, and surveys to the solar-powered electric boat had been designed previously for the race. Collected data are then used as input for the calculation and simulation of the vessel being designed. It is expected that the study could optimize the mechanical system of the solar-powered electric boat, and can be developed for recreational use in Indonesian waters.

关键词： Global warming

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Propulsion System Analysis For Solar-Powered Electric Water Recreational 3

Propulsion System Analysis For Solar-Powered Electric Water ...

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3rd International Tropical Renewable Energy Conference on Sustainable Development of Tropical Renewable Energy (i-TREC)

作者： Sunaryo Nurachman, Dendi Univ Indonesia Dept Mech Engn Naval Architecture & Marine Engn Study Program Temple Depok 16424 Indonesia

Indonesia is the world's largest archipelago with more than 17,000 islands, and also the best marine tourism destination, there are many beautiful beaches and underwater spots throughout the country. Due to this potential condition Indonesian government is planning to improve its maritime tourism sector. To realize this boats play very important role both for transport as well as for recreational purposes. On the other hand the government is also committed to reduce the global warming from the use of fossil fuel especially in industry and transportation through the Presidential Regulation no. 61/2011, with the strategy for replacing the fossil fuel with renewable energy. To support the government's program the research is aimed to design solar -powered electric recreation boat for tourism, with the consideration that there is almost non-stop sun shine available all year long in Indonesia. The boat has length of 12 meters. In this paper the focus is on the analysis of the propulsion system of the boat, which consists of the calculation the power needed to run the electric motor, the optimum propeller design, and the steering system.

关键词： Boats

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Economic Feasibility of a Small-Scale Wind Turbine in Coastal Area of South Sulawesi

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IOP Conference Series: Earth and Environmental Science 2021年第1期921卷

作者： F Mahmuddin N Puspitasari M U Pawara Marine Engineering Department Engineering Faculty Hasanuddin University Indonesia Naval Architecture Program Department of Science Food Technology and Maritime Kalimantan Institute of Technology Balikpapan Indonesia

To evaluate the exploitation potential of wind energy in the coastal area of South Sulawesi, Indonesia, an investigation on the economic feasibility of this project was performed. A 300-watt horizontal wind turbine was used as an example installed turbine. The wind speed range of 4-7 m/s which was the wind speed data in the coastal area of South Sulawesi was computed. The main economic analysis method employed was Capital Budgeting Analysis (CBA) method. In this method, 4 (four) indicators were used to evaluate the feasibility of the project which are payback period (PBP), net present value (NPV), internal rate of return (IRR), and benefit-cost ratio (BCR). A visual basic computer program based on the CBA method was also developed to make the computation more convenient. From the study, it was found that the wind speed range of 4-6 m/s resulted in a non-feasibility project while the highest wind speed (7 m/s) was found to be quite strong to make the project feasible.

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The Role of Social Influence in Blockchain Adoption: The Brazilian Supply Chain Case 9

The Role of Social Influence in Blockchain Adoption: The Bra...

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9th IFAC/IFIP/IFORS/IISE/INFORMS Conference on Manufacturing Modelling, Management and Control (IFAC MIM)

作者： Wamba, Samuel Fosso Queiroz, Maciel M. Toulouse Business Sch TBS Informat Operat & Management Sci F-31068 Toulouse CO France Paulista Univ UNIP Postgrad Program Adm BR-04026002 Sao Paulo SP Brazil Univ Sao Paulo Naval Architecture & Ocean Engn BR-05508030 Sao Paulo SP Brazil

The aim of this study is to understand the blockchain adoption behaviour in Brazilian supply chains Specifically, the study aims to unlock the potential of social influence;taking into consideration workers from the Brazilian supply chains We proposed a model using constructs from a unified theory of acceptance and the use of technology (UTAUT). The models were analysed using partial least squares structural equation modelling (PLS-SEM) and the findings indicated the power of social influence in predicting other UTAUT constructs. In addition, this study shows the mediation effect of effort expectancy and the facilitating conditions in the relationship between social influence and the behavioural intention to adopt blockchain Finally, our findings bring essential theoretical and managerial implications. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Blockchain UTAUT supply chain social influence facilitating conditions performance expectancy effort expectancy

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