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Marine Systems & Ocean Technology
Number of Followers: 1  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1679-396X - ISSN (Online) 2199-4749 Published by Springer-Verlag  [2468 journals]
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- A method for estimating the system reliability of ship grillage structure
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Abstract: Abstract A method for estimating the system reliability of the ship grillage structure under combined axial compression and lateral pressure load is presented in this paper. The ship grillage structure is idealized as a structural system consisted of several longitudinal stiffeners and transverse girders with attached plating in parallel, respectively. The ultimate compressive strength of the stiffener with attached plating under the combined axial compression and lateral pressure load is calculated by the analytical method. The lateral pressure load applied to the ship grillage structure is considered how to be distributed on the longitudinal stiffener and the transverse girder. The reliability on the buckling collapse of each stiffener with attached plating is estimated by Monte Carlo simulation method, and the system reliability of the ship grillage structure is estimated, considering the redistribution of the external load in other stiffeners after any of stiffeners fails. The uncertainties are quantified using probabilistic models of design variables proposed in the previous literature. By numerical example for the system reliability estimation of a stiffened panel under combined axial compression and lateral pressure load, the present method is validated.
PubDate: 2024-07-12
DOI: 10.1007/s40868-024-00143-y
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- Wave attenuation due to stratified porous structure in the presence of
stepped seabed-
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Abstract: Abstract The wave transformation due to the stratified porous structures in the presence of stepped seabed at leeward side is analysed based on the small amplitude wave theory. The study is performed to analyse the effectiveness of both horizontal and vertical stratified porous structure for the wave attenuation in the nearshore regions using orthogonal mode-coupling relation and eigenfunction expansion method. The hydrodynamic coefficients such as wave reflection, transmission, dissipation, wave force acting and surface elevation are investigated for both horizontally and vertically stratified porous structures. The effect of change in the structural properties such as varying porosity, friction factor, structural width, angle of incidence and length between the porous structure and stepped seabed are examined. Thereafter, the comparative study is performed for both horizontally and vertically stratified porous structure in the presence of stepped seabed and the numerical results are validated with the results available in the literature. The present study illustrates that with the increase in step height, the wave damping efficiency is enhanced. In addition, the wave energy dissipation is observed more for horizontally stratified structure in the case of longer waves whereas vertically stratified structure is effective in dampening of shorter waves. Further, the wave reflection and transmission for vertically stratified structure is found to be more for same length between structure and stepped seabed. The stepped seabed in leeward side in combination with vertical and horizontal stratified porous structure is intended to be an effective solution for protection of coastal facility.
PubDate: 2024-07-09
DOI: 10.1007/s40868-024-00141-0
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- Probabilistic assessment of optimum tuned mass damper in offshore
platforms considering fluid–structure interaction-
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Abstract: Abstract In countries with petroleum-based economies, offshore platforms are considered highly vital infrastructures that are subjected to various dynamic loads in their lifetimes. One effective way to reduce the vulnerability of these structures is to apply vibration control systems. This paper investigates the dynamic behavior of the Ressalat offshore platform under vibrations induced by wave-loading with a return period of 100 years in the Persian Gulf region. The Fluid–Structure Interaction (FSI) is considered along with the effect of the added mass which results from platform vibrations inside the fluid. The Modified Endurance Wave Analysis Method (MEWA) is utilized to load the platform. To control the vibrations of this platform, an optimized Tuned Mass Damper (TMD) was designed using a genetic algorithm. Then, probabilistic evaluation of the damper parameters was carried out via Latin Hypercube Sampling (LHS) method. Results represented that the maximum value of acceleration at the deck level has decreased by more than 45% due to the application of an optimally designed damper. An important point in this study is that the uncertainties of the optimal characteristics of the control system, cause reduction in the efficiency of the control system with the probability of 90% and makes improvement with the probability of 10%.
PubDate: 2024-07-09
DOI: 10.1007/s40868-024-00144-x
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- Operational efficiency and sustainability in smart ports: a comprehensive
review-
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Abstract: Abstract The challenges of optimizing logistics operations in all links of the supply chain have led to the development of new dynamics around the revolution 4.0 and the response of operational efficiency linked to environmental sustainability. Smart ports are born as a strategy to meet customer needs from a technological evolution that generates quality logistical and operational responses. The objective of this review is to identify and to analyze the research perspectives related to smart ports. The implemented methodology considered a scientific mapping to determine the most relevant publications in terms of authors, journals, and countries with the greatest scientific participation in the subject and a network analysis based on the implementation of the tree metaphor of the graph theory. The R-studio software and the Bibliometrix plugin were used to process the information. The review considered 204 documents from the Scopus and Web of Science databases, identifying a growing trend in the number of enhanced publications as of 2019, with China being the country with the largest number of papers. In relation to research trends, the adaptation of ports to industry 4.0, maritime ports and technological security, and green and smart ports are the perspectives on the subject of study. Finally, an agenda for future research is presented.
PubDate: 2024-06-27
DOI: 10.1007/s40868-024-00142-z
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- Blockage and submersion depth effects on horizontal-axis tidal turbine
(HATT) in a shear flow environment with wave–current interaction-
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Abstract: Abstract As one of the promising renewable energies, ocean renewable energy (ORE) in the form of tidal energy can be extracted through a horizontal-axis tidal turbine (HATT). HATT performance relies on various environmental factors, including the presence of waves, shear flow, blockage, and submersion depth. Several studies have been conducted regarding the effects of such factors on HATT’s performance. However, a coupled study on the mentioned environmental factors is yet to be performed. This study determines the effects of blockage and submersion depth on HATT’s performance designed for low-flow velocities experiencing shear flow with wave–current interaction through numerical simulations. The hydrodynamic analysis is done using CFD to determine the performance characteristics of the turbine, specifically the coefficients of thrust and power. For structural performance, a fatigue analysis is done through FEM to study the effects of stress loadings on the turbine. A wet epoxy/E-glass is utilized as the material of the turbine and a stress-life (S-N) analysis as the fatigue model. It is found that an increase in blockage ratio and submersion depth increases the coefficients of thrust and power, thus increasing the forces applied on the turbine blade. This result is due to the variation in fluid flow created by waves and current, which also leads to an increasing accumulation of stress and strain, with safety factors decreasing along with it. The parametric analysis shows a very strong relationship between the hydrodynamic and structural performance of the turbine, with absolute R-values ranging from 0.84 to 1.0. This study shows blockage ratio and submersion depth are essential considerations when designing HATTs.
PubDate: 2024-06-05
DOI: 10.1007/s40868-024-00135-y
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- Numerical investigation of the vortex-induced vibration of a circular
cylinder wrapped by a porous layer with time-dependent permeability-
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Abstract: Abstract This numerical study uses a two-dimensional finite volume method (FVM) to simulate the vortex-induced vibrations (VIVs) of an elastically mounted cylinder wrapped by a porous layer. The flow is incompressible, and the effects of mass ratio ( \(2\le {m}^{*}\le 10\) ), damping ratio ( \(0.01\le \xi \le 0.1\) ), and aspect ratio \((0.75\le {A}_{r}\le 1.5)\) on the lift force, pressure coefficients, and vibration response of a cylinder with constant Darcy number are investigated at Re = 150. Afterward, the dynamic response of the porous-coated cylinder with successive Darcy reduction is studied over a range of reduced velocities \((4\le {U}_{r}\le 14)\) for the first time to investigate the influence of gradual migration of suspended marine particles on the streamlines, flow wake, pressure contours, pressure coefficients, hydrodynamic forces, and vibration response of a vertically oscillating cylinder. According to the results, the influence of gradual Darcy reduction on \({{C}_{L}}_{rms}\) is significant at \({U}_{r}\) = 4 and 5 and reaches its maximum at \({U}_{r}\) = 6, where \({{C}_{L}}_{rms}\) increases by more than 100%. When the reduced velocity is increased from \({U}_{r}\) = 4, the effect of successive Darcy reduction on \({A}^{*}\) becomes more significant at some critical values of reduced velocity and shows a 70% increase at \({U}_{r}\) = 6. Moreover, \({f}^{*}\) slightly increases for all reduced velocities when the Darcy number decreases over successive periods. In this study, this successive Darcy reduction has an impact similar to that of the lock-in region. The normalized response frequency approaches one at \({6\le U}_{r}\le 8\) and creates a desynchronization regime to fully suppress the vibration amplitude at reduced velocities higher than those of the lock-in area. Moreover, when the cylinder undergoes high-amplitude oscillations, the effect of successive Darcy reduction on the flow wake increases the width of the lock-in region, where galloping (2P) occurs during the transition from the initial branch to the upper regime.
PubDate: 2024-05-23
DOI: 10.1007/s40868-024-00140-1
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- Analysis of spherical pressure hull subjected to underwater explosion
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Abstract: Abstract Spherical pressure hull for manned submersible may experience extreme environmental conditions. Damage assessment of the spherical pressure hull subjected to an underwater explosion of a mine or a depth charge or a gas explosion in offshore industries is very much required. This study focuses on elastic and inelastic numerical analysis on the spherical pressure hull of 2100 mm internal diameter and 65 mm thickness subjected to a non-contact underwater explosion. Numerical analysis is carried out in finite element analysis software ANSYS. Explosion can be defined by its intensity, which is a function of the mass of the explosive and distance between the structure and the detonation point. The amount of shock energy delivered by the explosion is defined by scaled distance, whereas the energy absorbed by the structure is defined by effective shock factor. Numerical analyses under elastic and inelastic conditions are carried out for different stand-off distances. Initially, the analysis is carried out using stress–strain curve. If the structure undergoes permanent deformation, then Cowper–Symonds material model is introduced to consider the strain rate effect. At a shock factor of 3.98 and scaled distance of 0.15, the spherical pressure hull undergoes a permanent deformation of 0.7 mm. Non-contact underwater explosion damage is predicted by numerical analysis to understand the elasto-plastic behavior of the spherical pressure hull.
PubDate: 2024-05-23
DOI: 10.1007/s40868-024-00138-9
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- Interannual and interseasonal variability of the persian gulf surface wave
energy in the recent decade-
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Abstract: Abstract Renewable energies play an important role in global energy production. Wave energy is a type of renewable energy that can be affected by climate change. This study aims to investigate the distribution of surface wave energy variability over the Persian Gulf in the recent decade (2009–2018). To this end, Interannual and Interseasonal variability of the surface wave energy has been investigated using the Simulating Waves Nearshore (SWAN) numerical model and applying statistical methods, including trends and Empirical Orthogonal Function (EOF) analysis. The results indicated that the wave energy in most areas of the Persian Gulf showed a significant increasing trend although there was a negative trend value in the southwest of the Persian Gulf and no significant change in the southern coastal area of the Arabian Peninsula. The climatology of wave energy showed the seasonal variability of the wave energy, with a stronger value in the central parts of the Persian Gulf (50°–53° E) during winter months and reducing during spring months, especially in April. Then it reaches its maximum value in June and declines throughout the summer and fall months. Mean wave energy in 2017 had its maximum value due to destructive Meteotsunami -like waves that impacted the Persian Gulf in 2017 and its minimum were occurred in 2009, 2010, and 2014. In addition, the first principal component (PC-EOF 1), suggests a possible influence from the winter Shamal wind event and shows that the wave dynamics was closer to unimodality, in the period of study.
PubDate: 2024-05-17
DOI: 10.1007/s40868-024-00139-8
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- Robust depth position tracking control of an AUV using $$H_{\infty }$$
synthesis-
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Abstract: Abstract This paper addresses the tracking control for the diving motion of an autonomous underwater vehicle (AUV). The primary control objective is to effectively track the desired depth position, in the presence of parametric uncertainties, underwater disturbances, and input delays. A third-order linearized model is employed to describe the dynamics of the diving system. This dynamic system comprises an inner pitch control loop and an outer depth control loop, each intended for independent control. In order to achieve this, a cascade control structure is adopted for control synthesis. In this context, \(H_{\infty }\) control law for the inner pitch control loop and a proportional (P) control law for the outer depth control loop are proposed, aiming to attain the specified control objectives. The robustness of the control design accounts for parametric uncertainties within the nominal model, input delays, and external disturbances, such as ocean currents. The closed-loop stability of the proposed controller is verified, and closed-loop performance is evaluated through a series of various simulation studies. To maintain practical relevance, we used the experimentally validated parameters of AUV REMUS 100 in the simulation model. The performance of the proposed control scheme is compared with two benchmark control scheme, namely proportional-derivative plus proportional ( \(PD+P\) ) and \(H_{2}\) control. The comparison considers parametric uncertainties, underwater disturbances, and input delay.
PubDate: 2024-04-12
DOI: 10.1007/s40868-024-00137-w
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- Ocean quadcopters: persistent and autonomous aerial surveillance of large
maritime areas by quadcopters self-powered by ocean waves-
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Abstract: Abstract In this work consideration is given to the possibility for persistent aerial surveillance of oceans by means of quadcopters capable of taking off and landing on the sea and charging their batteries by the waves from the ocean. Clusters of relatively inexpensive ocean quadcopters equipped with conventional CCD cameras could be scattered over large and abandoned maritime areas to perform continuous and random aerial surveillance of the region. Utilizing a simple physical model, the feasibility of this novel approach for monitoring large maritime areas is assessed. Additional R & D is required in order to explore the possibilities offered by oceans quadcopters
PubDate: 2024-03-15
DOI: 10.1007/s40868-024-00134-z
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- Wells turbine power enhancement by simultaneous and opposite motion of the
turbine-chamber system-
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Abstract: Abstract In this note, consideration is given to a possible practical strategy by which the power from a Wells turbine in an oscillating water column could be enhanced. In this strategy and contrariwise traditional approaches in which turbine and chamber are at rest, the motion of the turbine and the chamber are both in motion and driven by a common heaving float. However, while the motion of the turbine is in one direction, the motion of the chamber is reversed owing to a lever or pulley system. In this way, from the point of view of the turbine framework the relative velocity of air passing through the Wells turbine may be, idealized, doubled and thus the extractable power output. The strategy could also be used in linear inductance generators in which case by doubling the relative velocity between coil and magnet which taking into account that the electrical power is related to the square of relative velocity the strategy is worthy to be considered.
PubDate: 2024-03-04
DOI: 10.1007/s40868-024-00136-x
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- Linear quadratic regulation for a 10-MW tension leg platform floating
offshore wind turbine operating under normal and extreme turbulence model
conditions-
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Abstract: Abstract New concepts of floaters have been developed for multimegawatt wind turbines aiming to reduce the cost of renewable energy generation in deep waters. This paper presents the preliminary design and tuning of a linear quadratic regulator (LQR) for a floating offshore wind turbine (FOWT) constituted of the DTU 10-MW offshore reference wind turbine (RWT) and the CENTEC-TLP tension leg platform (TLP). The goal of the LQR is to improve the performance of the 10-MW CENTEC-TLP FOWT above the rated wind speed using the collective blade pitch actuator within the saturation limits. The LQR design is based on a verified control-oriented FOWT model considering the measurement of surge and pitch floater motions in addition to the rotor speed. Wind and wave disturbances are assumed to be unmeasured. The LQR performance is evaluated for two above-rated operational cases, involving normal and extreme turbulence models combined with relevant sea states. Simulation results show that the designed LQR can yield a reduction of approximately 67% in the rotor speed and power standard deviations compared with a baseline proportional-integral (PI) controller. With the baseline controller, the maximum rotor speed and maximum electrical power are about 15% higher than the rated speed and power, respectively, while this value is reduced to about 6% with the LQR controller. The designed LQR can also yield a TLP pitch reduction of approximately 21%, while keeping the surge amplitude and nacelle axial acceleration below their respective limits.
PubDate: 2024-02-08
DOI: 10.1007/s40868-023-00133-6
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- Iceberg draft prediction using gradient boosting regression algorithm
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Abstract: The Arctic area is one of the best destinations for the development of oil and gas loading equipment. However, the recent development of oil and gas facilities, including the submarine pipelines and wellheads crossing the Arctic area, has elevated the need for more attention to iceberg draft (under-water height of icebergs) estimation during an ice scouring event. This means if the draft of an iceberg is more than the ocean deepness, the iceberg tip can gouge the ocean floor and collide with the subsea assets; as a result, the operational integrity of the submarine infrastructures is threatened. Hence, the estimation of the iceberg drafts is vital for the oil and gas operators in the Arctic waters. In the present study, the use of the Gradient Boosting Regression (GBR) algorithm was proposed to simulate the iceberg drafts for the first time. Initially, the parameters governing the iceberg drafts were recognized, and nine GBR models were then developed. The premium GBR model along with the most important inputs was known by conducting a sensitivity analysis, e.g., the value of correlation coefficient (R) and Akaike Information Criteria (AIC) for the premium GBR model was obtained at 0.907 and 12.571, while the iceberg length ratio (L⁄H) and iceberg width ratio ( \(W/H\) ) were recognized as the most influential input parameters to predict the iceberg drafts. The best GBR model was compared with Support Vector Regression (SVR) and K-Nearest Neighbors Regression (KNR) algorithms, rather the GBR algorithm had the highest degree of accuracy and correlation as well as the lowest amount of complexity. The error analysis demonstrated that roughly 34% of the iceberg draft predicted by the premium GBR model had an error of less than 10%; however, this value for the SVR and KNR models was almost 19%. Lastly, the performed uncertainty analysis proved that the superior GBR model possessed the narrowest bound of uncertainty, with an overestimated performance in the iceberg draft simulation. Graphical
PubDate: 2024-01-08
DOI: 10.1007/s40868-023-00132-7
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- Surrogate models for the stiffened catenaries: applications in subsea pipe
laying-
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Abstract: Abstract In this paper, the governing nonlinear ODE of the suspended stiffened catenary is reinvestigated. It is shown that strong nonlinearity arises from stiffened catenary length, which should be checked by an iterative numerical solution. The two concepts of stiffened catenary (guessed length) and natural catenary (known length) geometries of the suspended pipe, are compared and critically commented upon. In applying the theory to subsea pipeline installation, it is shown that natural catenary assumption, underestimates the installation stresses, particularly in shallow water and low laying depth. However, the true values of the stresses can be computed via stiffened catenary theory, in which the bending stiffness of the suspended pipe is not ignored. Thereafter, substantial iterative numerical solution of the governing nonlinear differential equation, in each load case is carried out. From these batch simulations, a surrogate expression is developed via optimization techniques. This model provides a correction factor by which, the accurate installation stress can be found. Moreover, the accuracy of results is verified by FEM analysis. It is concluded that for the initial estimation of the stresses, the simple natural catenary assumption, which is currently practiced can be used. However, the results should be corrected by the new surrogate expression, that has been produced in this paper. This can eliminate the underestimation of the installation stresses when a simple computational procedure is used.
PubDate: 2023-11-29
DOI: 10.1007/s40868-023-00131-8
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- MURA: a Multipurpose Underwater Robotic Arm mounted on Kalypso UUV in
aquaculture-
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Abstract: Abstract Underwater vehicles utilized in net cages at aquaculture facilities are commonly utilized for the purpose of examining the deterioration of nets and the accumulation of biofouling. The implementation of a robotic system for repairing damages has the potential to decrease the expenses associated with employing divers while reducing the risk of their injury. This study details the development, fabrication, and simulation of a cost-effective subaquatic manipulator, denoted as MURA, which can be seamlessly incorporated into submersible vehicles. The Kalypso unmanned underwater vehicle (UUV) is utilized in this study. MURA exhibits a high degree of modularity, enabling seamless alteration of the end-effector tool. Additionally, its low-cost nature renders it a viable option for integration with any underwater vehicle. Three end-effectors were subjected to testing, one designed for the purpose of disposing fish morts, another intended for removing litters from net cages in fisheries, and a third for repairing net tears. This study outlines the MURA design, including the arm’s fabrication and constituent components. In addition, the modeling of the manipulator is presented accompanied by a water flow simulation of the three manipulators. Ultimately, the experimental findings are analyzed and evaluated. These include the field experiments performed at Kefalonia fisheries, along with the duration to complete each task. For instance, the capture of fish morts typically necessitates approximately 30 s, encompassing the entire process from initial targeting to actual capture. In a similar vein, the procedure of mending tears in a net necessitates an approximate duration of 70 s on average, encompassing the stages of initial identification and subsequent detachment. The suggested design exhibits adaptability and durability while upholding affordability when utilized in aquaculture.
PubDate: 2023-11-16
DOI: 10.1007/s40868-023-00129-2
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- CFD optimization of a displacement catamaran’s configuration for
minimized calm water resistance-
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Abstract: Abstract In this paper, a CFD simulation of the flow about a displacement catamaran model (Delft 372 catamaran model) is carried out over a range of forward speeds by solving the Reynold Average Navier–Stokes equation (RANSE). The Shear-Stress Transport (SST) turbulence model is selected, and the volume of fluid (VOF) method is adopted to capture the free surface flow about the catamaran. Results are validated by comparison with experimental data available in the literature. The aim of this study is to investigate the effect of the separation–length ratio and the non-parallel configuration of the demi-hulls on the total resistance and wave pattern generated by the catamaran over a range of forward speeds. Subsequently, the Response Surface Method for optimization is applied at a particular Froude number and over a selected range of separation–length ratios and non-parallel configurations of the demi-hulls to provide minimum total resistance. Obtained results are satisfactory with a reduction in the total resistance at about 5% as compared to that of the original configuration.
PubDate: 2023-01-03
DOI: 10.1007/s40868-022-00123-0
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- Oblique wave propagation through composite permeable porous structures
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Abstract: Abstract In the present study, the porous breakwater system consisting of a porous block and a permeable barrier is analysed to understand the wave dissipation due to the composite porous structure. The linearised wave theory is adopted to analyse the wave interaction with three different configurations of the composite structures including (a) porous structure and fully extended vertical barrier, (b) porous structure and bottom-standing barrier and (c) porous structure and surface-piercing barrier. The eigenfunction expansion method along with orthogonal mode-coupling relation is adopted to determine the wave reflection and transmission characteristics along with wave force on the porous structure and barrier, and surface deflection in incident and transmitted region. The experimental investigation is performed for the composite breakwater system and the results obtained are compared and validated with the numerical results. The composite breakwater system is studied for various parameters such as relative water depth, porosity of structure and barrier, structural thickness to wavelength ratio, water depth to wavelength ratio and gap between the structure and barrier. Further, the comparative study is performed with the results available in the literatures. The proposed study exhibits an informative result for the wave energy attenuation by the composite breakwater system which can be designed and implemented in coastal and harbour regions for achieving the tranquillity.
PubDate: 2022-12-20
DOI: 10.1007/s40868-022-00122-1
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- Experimental study of an oscillating water column wave energy converter
based on regular waves-
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Abstract: Abstract Increasingly, marine renewable energies are taking over as one of the most relevant solutions to minimize dependence on fossil fuels. The management and exploitation of such energy requires the optimization of converters that will, later on, ensure the conversion of hydraulic energy into electrical energy; among these converters are the oscillating water column. An OWC is characterized by its simplicity and its effectiveness against turbulent ocean conditions. The performance of OWCs depends strongly on the geometrical parameters of the air chamber such as: chamber walls, width, thickness of the front wall, slope at the bottom of the chamber and size of the opening. In this sense, the manuscript presents a parametric approach to investigate, by experimental tests, the hydrodynamic properties and the performance of oscillating water column wave energy converter (OWC). The effects of some geometrical key parameters of the system are analyzed. The tests are carried out on a small‐size OWC. The work seems to be interesting in view of its experimental aspect. We have realized a prototype of an oscillating water column (OWC) which consists of a box (an air chamber) having the shape of parallelepipeds. The experimental results found by this study showed different optimums of: (a) the distance between the wave generator and the device (2 positions). (b) The depth of water in the hydraulic channel. (c) The immersion depth of the front wall of the chamber. (d) The opening at the bottom of the prototype. The results obtained show that the coupling of the geometrical parameters of the device and the conditions of installation leads to an improvement of the hydrodynamic performances of the OWC. The study also shows that the various optimums found give a considerable increase in the energy output.
PubDate: 2022-11-11
DOI: 10.1007/s40868-022-00121-2
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- A comprehensive review on exploration and exploitation of offshore
geothermal energy-
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Abstract: Abstract World’s ocean has abundance of geothermal energy. Exploration and exploitation of the same is in nascent stage. Several exploration sensors like magnetic, optical, chemical, etc., are towed from ships to sea floor for exploration. Several researches are carried out for drilling these explored hot spots. Once the energy is exploited, the same is transferred to power plant located on land. In this paper, three different types of power plants are discussed namely onshore power plant, offshore power plant, and power generation using the thermoelectric method. This paper narrates the current status of offshore geothermal technology which also includes the technology readiness level of this method. The paper also mentions the parameters which are required for designing of offshore geothermal power plants. Along with the technical aspects of offshore geothermal exploration and exploitation, this paper also talks about the environmental impact of these techniques on marine life. Demonstrative case studies from Indonesia and Italy are presented in this paper. The technical and economic study of the case studies are also briefed. The learnings from these countries may be utilized for the exploration and exploitation of offshore geothermal hotspots of India. Through this paper, it will be easy to understand the technical, financial, and environmental aspects of offshore geothermal technology for developing countries in the field of geothermal.
PubDate: 2022-10-24
DOI: 10.1007/s40868-022-00120-3
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- Two-dimensional modelling of free-surface flows in presence of a spherical
object using the Modified Volume of Fluid technique-
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Abstract: Abstract In this paper, a two-dimensional numerical simulation of water entry of a spherical object is achieved using the Modified Volume of Fluid (MVOF) technique. Continuity and Navier–Stokes equations along with an equation for tracking the free-surface motion are considered as the governing equations for 2D incompressible fluid flow. The free-surface deformation is modelled via integration of the fast fictitious domain method into the MVOF technique. The computational domain includes everywhere even the spherical object where the governing equations are solved. A rigid motion of the spherical object is generated by applying the linear and angular conservation laws. To exert the no-slip condition on the solid–liquid interface implicitly, the viscosity of the region arranged within the solid object is increased artificially. The numerical results obtained using the MVOF method are compared with those of the experiments in the literature and the conventional Volume of Fluid method. The results show that the effects of the artificial compression term on the free-surface deformation is very dominant for coarse meshes while this factor becomes minor for fine meshes.
PubDate: 2022-09-29
DOI: 10.1007/s40868-022-00117-y
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