Browsing by Author "Huang, Luofeng"
Now showing 1 - 20 of 37
Results Per Page
Sort Options
Item Open Access A study into the correlation between single array-hull configurations and wave spectrum for floating solar photovoltaic systems(Elsevier BV, 2024-11-15) Jifaturrohman, Mohammad Izzuddin; Utama, I Ketut Aria Pria; Putranto, Teguh; Setyawan, Dony; Huang, LuofengFloating photovoltaic (FPV) systems offer a viable renewable energy solution due to easy installation and cost-effectiveness compared to other renewable energy generation methods. On the other hand, land-based solar photovoltaics face challenges such as space scarcity and environmental impacts. Shifting to nearshore locations unlocks vast ocean space potential, though waves expose significant challenges to FPV systems. Several novel FPV system designs are proposed, inspired by high-speed vessel multihulls, including catamaran, trimaran, quadrimaran, and pentamaran configurations, as floating supports for solar panels. Simulations were conducted to determine Response Amplitude Operators (RAOs) under various irregular wave spectrum conditions in a free-floating initial state. The FPV motion problem was solved using linear potential-flow theory with the Boundary Element Method (BEM) with Green-Function approach. Superposition of wave spectral energy and motion RAOs was used to obtain spectral structural responses. Motion in heave, roll, and pitch modes was evaluated across wave spectrum types. Results show that adding hulls reduces the significant amplitude response in all motion modes. In summary, valuable insights into floater designs and the hydrodynamic evaluation of FPV systems are presented.Item Open Access Array analysis on a seawall type of deformable wave energy converters(Elsevier, 2024-03-24) Wei, Yujia; Wang, Chao; Chen, Wenchuang; Huang, LuofengThere has been a significant interest in developing Flexible Wave Energy Converters (FlexWECs) that utilise structural deformations to generate electricity and mitigate destructive wave loads to the devices. In the meantime, FlexWECs are most likely to operate in an array format to enhance space usage and power output, as well as provide convenience for maintenance. In this context, the present paper develops a high-fidelity computational model to investigate the interaction of ocean surface waves with an array of seawall-type FlexWECs, which can meanwhile serve coastal engineering purposes. The fluid field is solved using the Navier-Stokes equations, and structural deformations are predicted using a nonlinear finite-element method. Hydroelastic interactions of up to seven deforming FlexWECs with the surrounding wave fields are demonstrated through systematic simulation cases. Based on the simulation results, analyses are conducted to investigate how the wave farm energy output is influenced by the gap between individual devices and the number of devices deployed. Accordingly, empirical design suggestions are provided. Overall, this work innovatively simulates the hydroelastic interactions between waves and multiple deforming structures, and the provided insights are useful for promoting the development of FlexWECs and their wave farms.Item Open Access A combined experimental and numerical approach to predict ship resistance and power demand in broken ice(Elsevier, 2023-12-11) Xue, Yanzhuo; Zhong, Kai; Ni, Bao-Yu; Li, Zhiyuan; Bergstrom, Martin; Ringsberg, Jonas W.; Huang, LuofengDespite its remoteness and hostile environmental conditions, the Arctic holds significant shipping lanes, such as the Northern Sea Route (NSR) and the Northwest Passage (NWP). Typically, merchant ships operate along these routes in summer only, when the dominating type of ice is broken ice. A challenge of operating in such ice conditions is that there is no cost- and time-efficient method for predicting the resulting ice resistance, which makes route planning difficult, among others. To address this challenge, we present and analyze two complementary approaches to predict ship resistance in broken ice, of which one is experimental and the other numerical. The experimental approach makes use of a type of non-refrigerated synthetic model ice made of polypropylene, which makes it possible to test how a ship behaves in broken ice using a conventional non-refrigerated towing tank rather than an ice tank. The numerical approach, in turn, is based on the CFD-DEM method and can be used to consider fluid effects, such as the changes in fluid velocity and ship waves, while the ship is moving ahead. Validation calculations against established empirical approaches indicate that both approaches are reasonably accurate.Item Open Access Compression after impact behavior of asymmetrically tapered laminates: experimental and numerical studies(Elsevier BV, 2024-12-01) Yu, Xiaonan; Xu, Xiwu; Huang, Luofeng; Qin, Qing; Zhang, ChaoThis paper presents experimental and numerical studies on the compression after impact (CAI) behavior of composite tapered laminates. It introduces newly designed impact platforms and compression fixtures specifically tailored for the specimens. Drop-weight impacts are applied to the center of the specimens, and the resulting damage is briefly described. Compression tests are then conducted on both non-impacted and impacted specimens, with strain gauges used to monitor the strain distribution. Internal damage is detected using CT scanning and ultrasonic C-scan techniques. The numerical simulations are performed using ABAQUS/Explicit finite element analysis (FEA), incorporating an intra-laminar progressive damage model and an inter-laminar cohesive model, while additionally modeling resin pockets as elastomers. The simulation and experimental results indicate that before compression failure, impact damage in the thin section minimally affects the out-of-plane displacement, which is predominantly influenced by structural asymmetry. Stress concentration is observed at the junction between the thin and tapered sections in the compression test, while in the CAI test, stress concentration appears in the impact zone. The impact induces a notable shift in failure location and damage modes, resulting in decreased compressive strength, although the impact on stiffness remains minimal.Item Open Access Cost-benefit analysis of a trans-Arctic alternative route to the Suez Canal: a method based on high-fidelity ship performance, weather, and ice forecast models(MDPI, 2023-03-25) Li, Zhiyuan; Ding, Li; Huang, Luofeng; Ringsberg, Jonas W.; Gong, Hui; Fournier, Nicolas; Chuang, ZhenjuClimate change in recent years has produced viable shipping routes in the Arctic. However, critical uncertainties related to maritime operations in the Arctic make it difficult to predict ship speeds in ice and, thus, the voyage time and fuel costs. Cost–benefit analysis of alternative Arctic routes based on accurate environmental condition modeling is required. In this context, this paper presents a holistic approach that considers the major voyage-related costs of a trans-Arctic route as an alternative to the conventional routes via the Suez Canal Route (SCR) for existing merchant ships. This tool is based on high-fidelity models of ship performance, metocean forecasting, and a voyage optimization algorithm. Case studies are performed based on a general cargo vessel in operation to quantify realistic expenses inclusive of all the major operational, fuel, and voyage costs of the specific voyages. A comparison is made between the total costs of the trans-Arctic route and SCR for different seasons, which proves the economic feasibility of the trans-Arctic route. Overall, this work can provide valuable insights to help policymakers as well as shipbuilders, owners, and operators to assess the potential cost-effectiveness and sustainability of future Arctic shipping, thereby better developing future strategies.Item Open Access Coupled analysis between catenary mooring and VLFS with structural hydroelasticity in waves(Elsevier, 2023-09-12) Wei, Yujia; Yu, Shuangrui; Jin, Peng; Huang, Luofeng; Elsherbiny, Khaled; Tezdogan, TahsinThe rapid growth of marine renewables has led to the development of very large floating structures (VLFS) that are designed to operate in deep seas. It is significant to understand the mechanism of the coupled effects between deformable VLFS and catenary mooring system. This paper presents a time-domain hydro-elastic-moored model developed by integrating a quasi-static mooring module into a fully coupled Computational Fluid Dynamics (CFD) - discrete-module-beam (DMB) approach. The model is used to investigate the coupled effects between structural hydroelasticity and loose-type mooring systems on a deformable VLFS in waves. The mooring and hydroelasticity codes are validated separately and show favourable agreement with other numerical and experimental results. Then the coupled effects between the mooring system and structural hydroelasticity are evaluated by assigning various design parameters, i.e., VLFS structural stiffness and mooring stiffness. The numerical results, including dynamic motions, longitudinal vertical bending moments (VBMs) and mooring tension forces are presented and analysed. These results can be used to design a VLFS with mooring in medium-deep sea, and help with the conventional mooring design for a less-stiffness VLFS due to hydroelastic response.Item Open Access COVID-19 transmission inside a small passenger vessel: risks and mitigation(Elsevier, 2022-05-19) Huang, Luofeng; Riyadi, Soegeng; Utama, I.K.A.P.; Li, Minghao; Sun, Peiyign; Thomas, GilesThe global shipping industry has been severely influenced by the COVID-19 pandemic; in particular, a significant amount of passenger transportation has been suspended due to the concern of COVID-19 outbreak, as such voyages confine a dense crowd in a compact space. In order to accelerate the recovery of the maritime business and minimise passengers' risk of being infected, this work has developed a computational model to study the airborne transmission of COVID-19 viruses in the superstructure of a full-scale passenger vessel. Considering the vessel advancing in open water, simulations were conducted to study the particulate flow due to an infected person coughing and speaking, with the forward door open and closed. The results suggest that keeping the forward door closed will help prevent the external wind flow spreading the virus. When the forward door is closed, virus particles' coverage is shown to be limited to a radius of half a metre, less than a seat's width. Thus, an alternate seat arrangement is suggested. Furthermore, investigations were conducted on the influence of wall-mounted Air Conditioner (AC) on the virus transmission, and it was found that controlling the AC outlet direction at less than 15° downward can effectively limit the virus spread. Meanwhile, it was demonstrated that an AC's backflow tends to gather virus particles in a nearby area, thus sitting farther from an opening AC may reduce the risk of being infected. Overall, this work is expected to inform hygienic guidelines for operators to counter COVID-19 and potentially similar viruses in the future.Item Open Access Energy efficiency analysis of a deformable wave energy converter using fully coupled dynamic simulations(MDPI, 2024-04-15) Luo, Chen; Huang, LuofengDeformable wave energy converters have significant potential for application as flexible material that can mitigate structural issues, while how to design the dimensions and choose an optimal deployment location remain unclear. In this paper, fully coupled computational fluid dynamics and computational solid mechanics were used to simulate the dynamic interactions between ocean waves and a deformable wave energy converter. The simulation results showed that the relative length to wave, deployment depth and aspect ratio of the device have significant effects on the energy conversion efficiency. By calculating the energy captured per unit width of the device, the energy efficiency was found to be up to 138%. The optimal energy conversion efficiencies were achieved when the structure length was 0.25, 0.5 or 0.75 of the dominating wavelength and submerged at a corresponding suitable depth. The aspect ratio and maximum stress inside the wave energy converter showed a nonlinear trend, with potential optimal points revealed. The simulation approach and results support the future design and optimisation of flexiable wave energy converters or other marine structures with notable deformations.Item Open Access Energy fluctuation of floating photovoltaic solar panel due to wave-induced motions(American Society of Mechanical Engineers, 2024-06-09) Huang, LuofengSolar photovoltaic is predicted to be the most widely used energy method in the future. However, the expansion of solar panels is currently limited by scarce land and lake spaces. To meet the world’s future clean energy target, floating solar panels are expected to be deployed on abundant ocean space, but floating solar panels on the ocean will be subject to loads and motions induced by waves. In particular, a continuous rotation can cause the solar panel surface to constantly change its sunlight intake angle, which could lead to a loss of energy. To investigate this phenomenon, a novel interdisciplinary experimental facility has been established, where a solar simulator was installed on top of a wave tank. A floating solar unit is placed in high-concentration light beams and subject to wave-induced motions. Its motions are measured and related to the power output. It was found that the average power output oscillates due to the motions, and an evident power loss was shown by the rotational motion. For all the tested wave conditions, the highest pitch amplitude of 6.7° corresponds to a significant level of 12.7% average power loss. Overall, the work presents a novel experimental approach and results that can estimate power output for floating solar projects in wave environments. The results also highlight the importance of considering wave attenuation technologies to avoid direct wave interaction with floating solar units.Item Open Access Floating PV systems as an alternative power source: case study on three representative islands of Indonesia(MDPI, 2024-02-05) Esparza, Ignacio; Olábarri Candela, Ángela; Huang, Luofeng; Yang, Yifeng; Budiono, Chayun; Riyadi, Soegeng; Hetharia, Wolter; Hantoro, Ridho; Setyawan, Dony; Utama, I. K. A. P.; Wood, Tim; Luo, ZhenhuaFloating solar renewable energy is of enormous potential in Indonesia. This paper presents a comprehensive study of the design of Floating Photovoltaic (FPV) systems with Battery Energy Storage Systems (BESS) for three islands in Indonesia. These islands represent three typical scenarios in Indonesia (a) using a national grid powered by fossil fuel generators, (b) using a local grid powered by diesel generators, and (c) no grid at all. In-person surveys were conducted at these islands to collect data, and then FPV and BESS were designed to meet the demands of each island. Subsequently, the systems’ energy simulations were conducted using the System Advisor Model, demonstrating daily energy demand and supply in hour variation. Based on the results, a series of sustainability analyses were created from the aspects of economics, society, and the environment. The economic analysis demonstrated cost savings by using FPV to replace contemporary energy methods. The social analysis provides valuable insights into the local community, forming a demographic profile and obtaining perceptions and opinions regarding the new energy approach. The environmental analysis quantifies the potential CO2 emissions. Overall, the work provides valuable insights into the roadmap for implementing floating solar technologies in Indonesia which can also inform global ocean-based solar energy developments.Item Open Access Floating solar power loss due to motions induced by ocean waves: an experimental study(Elsevier BV, 2024-11-15) Huang, Luofeng; Yang, Yifeng; Khojasteh, Danial; Ou, Binjian; Luo, ZhenhuaWhilst there is an interest in floating solar energy systems in coastal and offshore regions to utilise available sea space, they are subject to ocean waves that introduce constant momentum. Consequently, solar panels undergo periodic motions with the waves, causing a continuous change in tilt angle. The tilt angle variation is a sub-optimal process and leads to a loss of energy harnessing efficiency. To investigate this phenomenon, the present study innovatively installed a solar simulator on top of a wave tank. The solar simulator was used to generate high-strength light beams, under which, a floating solar unit was subject to periodic incident waves. Wave-induced motions to the solar system as well as the output power were measured. A systematic analysis of the results indicated that a floating solar unit can have significantly lower power output in waves, compared to its calm-water counterpart. An evident link was established between the wave-induced power loss and the wave-induced rotational movement of the panel. An empirical equation was derived which shows the power loss is predictable through the rotational amplitude. The results also highlight the importance of implementing wave attenuation technologies such as breakwaters to minimise wave-induced motions to floating solar systems. Overall, this research presents a novel experimental approach to assess the difference of floating solar power in ocean-wave versus calm-water scenarios, providing valuable insights for future solar projects on the ocean.Item Open Access Fully-coupled hydroelastic modeling of a deformable wall in waves(Elsevier, 2022-11-16) Hu, Zhengyu; Huang, Luofeng; Li, YuzhuThe hydroelastic behavior of a vertical wall in periodic waves is investigated using a fully-coupled computational fluid dynamics (CFD) and computational solid mechanics (CSM) model. The present numerical model is verified against previous numerical and experimental results on wave evolution and structural displacement. Then the hydrodynamic characteristics and the structural responses of an elastic wall in periodic waves are parametrically investigated. It is demonstrated that wave reflection, run-up, and loading decrease as the wall becomes more flexible. The decreases also occur when the waves become shorter. With nonlinear wave propagation, both the displacement and the stress of the wall are larger in the shoreward direction than those in the seaward direction. The wall displacement has the same frequency as the exciting waves and the stress increases with the decrease of the ratio of the wave frequency to the wall’s natural frequency. Considering the effect of flexibility, empirical formulae are proposed for predicting the wave run-up, loading, and maximum displacement of the wall. Besides, the optimization of the flexible wall is conducted by taking into account both the defense performance (i.e., transmission coefficient) and the structural integrity (i.e., maximum von Mises stress). Finally, the effect of the material damping is studied, which shows that the material damping has a negligible effect on the interaction between periodic waves and the elastic structure.Item Open Access Hydrodynamic analysis of a heave-hinge wave energy converter combined with a floating breakwater(Elsevier, 2024-01-02) Wei, Yujia; Yu, Shuangrui; Li, Xiang; Zhang, Chongwei; Ning, Dezhi; Huang, LuofengResearch interest in breakwater design has increased recently due to the impetus to develop marine renewable energy systems, as breakwaters can be retrofitted to harness wave energy at the same time as attenuating it. This study investigates a novel system of attaching a hinge baffle under a floating breakwater. The floating breakwater itself acts as a heaving wave energy converter, and meanwhile the hinge rotation provides a second mechanism for wave energy harnessing. A computational model with multi-body dynamics was established to study this system, and a series of simulations were conducted in various wave conditions. Both wave attenuation performance and energy conversion ratio were studied, using an interdisciplinary approach considering both coastal engineering and renewable energy. In particular, the performance of the proposed system is compared with contemporary floating breakwater designs to demonstrate its advantage. Overall, a useful simulation framework with multi-body dynamics is presented and the simulation results provide valuable insights into the design of combined wave energy and breakwater systems.Item Embargo Hydrodynamic performance of a three-unit heave wave energy converter array under different arrangement(Elsevier, 2023-12-17) Chen, Wenchuang; Huang, Zhenhai; Zhang, Yongliang; Wang, Liguo; Huang, LuofengA pile-restrained floating wave energy converter (WEC) array is proposed as an alternative to a single floater of the size of the array for use as a floating breakwater. The hydrodynamics of the WEC are modelled based on the Navier-Stokes equations and the model is verified by comparing its results with existing experimental data. The model then is used to characterize the array composed by a line of three WECs in terms of floater heaving, wave energy conversion, wave reflection, transmission and dissipation, for different layouts. In the examined array configuration, the aligned arrays exhibit superior performance compared to the staggered arrays, comprehensively considering both wave energy conversion and wave transmission. Specifically, when khi > 1.73, the wave energy conversion efficiency of the aligned array with a spacing of 0.1 times the WEC width ranges from 0.141 to 0.330, while the wave transmission coefficient ranges from 0.187 to 0.472, indicating the effectiveness of the arrays in simultaneously reducing wave transmission and converting wave energy under shorter-wavelength conditions. Compared to a single WEC of the same dimensions, the array exhibits a remarkable increase in wave energy conversion efficiency and effectively reduce wave reflection.Item Open Access Hydroelastic investigation on a pile breakwater integrated with a flexible tail for long-wave attenuation(Springer, 2022-11-10) Zhang, Chong-Wei; Zhuang, Qian-Ze; Li, Jin-Xuan; Huang, Luofeng; Ning, De-ZhiA novel concept of wave attenuator is proposed for the defense of long waves, through integrating a flexible tail to the lee-side surface of a pile breakwater. The flexible tail works as a floating blanket made up of hinged blocks, whose scale and stiffness can be easily adjusted. A two-phase-flow numerical model is established based on the open-source computational fluid dynamics (CFD) code OpenFOAM to investigate its wave attenuation performance. Incompressible Navier—Stokes equations are solved in the fluid domain, where an additional computational solid mechanics (CSM) solver is embedded to describe the elastic deformation of the floating tail. The coupling of fluid dynamics and structural mechanics is solved in a full manner to allow assess of wave variation along the deforming body. The accuracy of the numerical model is validated through comparison with experimental data. Effects of the flexible tail on performance of the pile breakwater are investigated systematically. Dynamic behaviours of the tail are examined, and characteristics of its natural frequency are identified. For safety reasons, the wave loads impacting on the main body of the pile breakwater and the stress distribution over the tail are specially examined. It is found that both the length and stiffness of the tail can affect the wave-attenuation performance of the breakwater. A proper choice of the length and stiffness of the tail can greatly improve the long-wave defending capability of the pile breakwater. The maximum stress over the flexible tail can be restrained through optimising the deformation and stiffness of the tail.Item Open Access Hydroelastic modelling of a deformable wave energy converter including power take-off(Elsevier, 2024-11-01) Wang, Chao; Wei, Yujia; Chen, Wenchuang; Huang, LuofengGiven the advantages of flexible wave energy converters (FlexWECs), such as deformation-led energy harnessing and structural loading compliance, there has been a significant interest in FlexWECs in both academia and industries. To simulate the FlexWEC interaction with ocean surface waves, a 3D computational fluid-structure interaction approach is developed in this study. The fluid and solid governing equations are discretized using finite difference and finite element methods, respectively. An immersed boundary method is used to couple the two independent grid systems. A novel numerical technique is introduced to model the dielectric elastomer generator (DEG) as the power take-off (PTO). The wave energy capture performance is analysed for different PTO configurations and at various wave conditions. Based on the obtained results, the PTO damping coefficient and the relative wavelength range that maximizes the capture width ratio (CWR) are determined. The wavefield results also reveal the presence of wave-height enhancement and attenuation points around a single FlexWEC, providing potential site selection references when deploying multiple FlexWECs in an array.Item Embargo Improving wave energy conversion performance of a floating BBDB-OWC system by using dual chambers and a novel enhancement plate(Elsevier, 2024-03-23) Chen, Wenchuang; Xie, Weixin; Zhang, Yongliang; Wang, Chen; Wang, Liguo; Huang, LuofengIn this study, a novel floating dual-chamber backward bent duct buoy oscillating water column (BBDB-OWC) wave energy converter (WEC) is introduced, featuring a horizontal plate at the bottom of the front chamber to act as an enhancement plate. A three-dimensional computational fluid dynamics (CFD) model is developed and validated by comparing its results with existing experimental measurements. The validated model is employed to investigate the hydrodynamic performance and power generation characteristics of the dual-chamber BBDB-OWC WEC under various conditions, including variations in the length of the horizontal plate (lp/lf) and different regular wave conditions. Key performance metrics, including peak to average ratio of power (PTARP), wave energy capture width ratio (ξtotal), and its wave period respond bandwidth (indicated by Pξtotal > 0.5 and Pξtotal > 0.7), are analyzed and compared with those of a traditional single-chamber BBDB-OWC WEC. The results reveal that, compared to the single-chamber WEC, the dual-chamber WEC with a specific horizontal plate length reduces the average PTARP from 2.88 to a minimum value of 1.82 for lp/lf = 0.5, improves the average ξtotal from 0.55 to a maximum value of 0.64 for lp/lf = 2.5, and increases Pξtotal > 0.5 and Pξtotal > 0.7 from 71 % and 14 % to maximum values of 86 % and 43 % for lp/lf = 2.5, respectively. An explanation for these observations is also provided in the context of structure motion and flow fields.Item Open Access Interactive effects of deformable wave energy converters operating in close proximity(Elsevier BV, 2024-11-01) Wang, Chao; Wei, Yujia; Chen, Wenchuang; Huang, LuofengFlexible wave energy converters (FlexWECs) have been gaining increasing research and industrial interest as their deformable nature can potentially remedy the structural issues that limit the development of rigid WECs. To maximise the usage of space and infrastructure and improve energy efficiency, FlexWECs are normally deployed in close proximity, where the wave interaction with one device can influence others, signifying the opportunity to obtain energy efficiency enhancement from the interactions. To investigate the power capture performance of a FlexWEC array, this study employed a validated three-dimensional high-fidelity computational method to simulate the wave interaction with three FlexWECs in various array arrangements including power-take off. Based on systematic simulation cases, the present work analysed the relation between the geometrical characteristics of an isolated FlexWEC's perturbed wave field and the array's overall energy capture efficiency. The constructive interaction of the array was found the strongest when the longitudinal and lateral spacings of the array were 0.6 and 1 times of incident wavelength respectively, with a 15 % enhancement of overall captured energy compared to three devices operating in isolation. Overall, this study provides insights into the fluid-structure interaction of waves with multiple deformable structures, facilitating the modelling and planning of FlexWECs.Item Open Access An investigation on the speed dependence of ice resistance using an advanced CFD+DEM approach based on pre-sawn ice tests(Elsevier, 2022-09-18) Huang, Luofeng; Li, Fang; Li, Minghao; Khojasteh, Danial; Luo, Zhenhua; Kujala, PenttiOver the past decades, the underlying mechanism of level ice resistance changing with ship speed has not been fully understood, particularly the resistance component due to ship interactions with broken ice pieces. Pre-sawn ice test can negate icebreaking component from the whole resistance of a ship in level ice, providing an effective approach to decompose ship-ice interactions and investigate the speed-dependent resistance from broken ice pieces. This work has built a computational model that can realistically simulate a ship advancing in a pre-sawn ice channel. The model applies Computational Fluid Dynamics (CFD) to solve the flow around an advancing ship, which is coupled with an enhanced Discrete Element Method (DEM) to model pre-sawn ice pieces. Model-scale experiments have also been conducted at the Aalto Ice Tank to validate the simulations, which shows the computational model can provide a reasonable estimation of the pre-sawn ice's resistance and movement around the ship. Upon validation, the dependence of ice resistance on ship speed was analysed. The simulations enable underwater monitoring of the ice motions, indicating that the speed dependence results from the mass of ice submerged underneath the ship and the displacement of broken ice induced by the ship. The identified relationships are more complex than the widely-used assumption that ice resistance linearly changes with ship speed in all cases, which provides a deeper understanding of ice resistance. As such, the findings from this study can potentially facilitate improvements in relevant empirical equations, useful for ship design, operational strategies and maritime management in polar regions.Item Open Access A large-scale review of wave and tidal energy research over the last 20 years(Elsevier, 2023-06-12) Khojasteh, Danial; Shamsipour, Abbas; Huang, Luofeng; Tavakoli, Sasan; Haghani, Milad; Flocard, Francois; Farzadkhoo, Maryam; Iglesias, Gregorio; Hemer, Mark; Lewis, Matthew; Neill, Simon; Bernitsas, Michael M.; Glamore, WilliamOver the last two decades, a large body of academic scholarship has been generated on wave and tidal energy related topics. It is therefore important to assess and analyse the research direction and development through horizon scanning processes. To synthesise such large-scale literature, this review adopts a bibliometric method and scrutinises over 8000 wave/tidal energy related documents published during 2003–2021. Overall, 98 countries contributed to the literature, with the top ten mainly developed countries plus China produced nearly two-thirds of the research. A thorough analysis on documents marked the emergence of four broad research themes (dominated by wave energy subjects): (A) resource assessment, site selection, and environmental impacts/benefits; (B) wave energy converters, hybrid systems, and hydrodynamic performance; (C) vibration energy harvesting and piezoelectric nanogenerators; and (D) flow dynamics, tidal turbines, and turbine design. Further, nineteen research sub-clusters, corresponding to broader themes, were identified, highlighting the trending research topics. An interesting observation was a recent shift in research focus from solely evaluating energy resources and ideal sites to integrating wave/tidal energy schemes into wider coastal/estuarine management plans by developing multicriteria decision-making frameworks and promoting novel designs and cost-sharing practices. The method and results presented may provide insights into the evolution of wave/tidal energy science and its multiple research topics, thus helping to inform future management decisions.