Wave resonance in the gaps formed by a four-float array for various drafts and incident wave frequencies is investigated using a numerical wave tank based on OpenFOAM. In the gap perpendicular to the direction of wave propagation, the resonant wave height is higher than that between two side-by-side floats under the same draft, and the resonant frequency is also different. Significant variations in wave height distribution are observed along the gap parallel to the wave propagation direction under different incident wave frequencies. When the incident wave frequencies are higher than the resonant frequency, the lateral force amplitude on the front floats increases, while the force amplitude on the rear floats does not show this effect. Using the dynamic mode decomposition method, we discover that the irregular distribution of wave heights across different frequencies leads to an increase in the lateral force amplitude on the front floats at non-resonant frequencies.

Ocean current energy is a stable, reliable, and highly predictable renewable energy source. The effective development of ocean current energy conversion technology is beneficial in addressing the issue of power shortage. However, the majority of current velocities worldwide are below 1.5 m/s, limiting the feasibility of using conventional current energy capture devices. This paper presents a vortex induced vibration based deep sea microfluidic eel energy capture device (VIV-EEL) designed to efficiently harness energy in low-speed current environments. The system employs Computational Fluid Dynamics (CFD) to develop a series of computational models that couple underwater multibody fluid-solid interactions. These models are subsequently validated through experiments. The study analyzed the flow field of VIV-EEL under different working conditions and discussed the impact of several dimensional parameters of the elastically supported cylinders, structural parameters of raft plates, and flow velocity on the hydrodynamic performance. The results demonstrate that the energy capture efficiency of VIV-EEL is enhanced by the vorticity vibration effect. It is evident that there exists an optimal radius size for the elastic support column to achieve the most favorable resonance effect in the flow field of VIV-EEL. The energy capture characteristics of the raft plate show a linear relationship with its structural parameters, enabling quantitative design according to the requirements of the power take-off system (PTO). Moreover, VIV-EEL exhibits a lower start-up flow velocity compared to traditional current energy capture devices, enabling it to initiate and capture energy at a flow rate of 0.3 m/s. This innovative solution offers technical support for efficient low-speed current energy capture.

Wave energy and ocean current energy are considered stable, reliable, and highly predictable renewable energy sources. The development of ocean current energy conversion technology is crucial in addressing power shortages. However, the low velocity of most ocean currents worldwide, typically less than 1.5 m/s, poses a challenge for traditional ocean current energy capture devices. Current estimations of power generation from underwater devices often significantly differ from actual results. This study presents an eel-type power generation device designed for underwater use, investigates the design and optimization of a hydraulic power take-off (PTO) system suitable for such devices, and examines key components of the hydraulic PTO system like variable hydraulic motors and generators. Analytical research was conducted to understand its operational characteristics, with a focus on components such as the accumulator, speed control valve, and energy storage flywheel. The article also delves into the hydrodynamic and energy conversion characteristics of the device under shallow water wave and current conditions, enhancing the hydraulic PTO system model and establishing an integrated calculation model for real-time data transmission during the calculation process. Through evaluations of pitch angle and power generation under varying sea conditions, the study explores the impact of hydraulic motor displacement and damping coefficient on the hydrodynamic and power generation characteristics of the device, further validated through sea trials. The study findings indicate a high level of parameter adaptation among the components of the hydraulic system. The addition of an accumulator to the system results in smoother output response curves, suggesting that the accumulator absorbs impacts and stabilizes the hydraulic power transmission system. The proposed comprehensive calculation method enables a more precise prediction of the performance of the eel power generation device in real marine environments, capturing its movement behavior and power generation characteristics. Adjusting the motor displacement or damping coefficient under specific conditions can optimize the total damping of the hydraulic PTO system for maximum power output. The optimal power point of the hydraulic power generation system varies for different sea conditions, with a potential power generation efficiency of up to 80.3% under certain circumstances.

With the rapid development of the Internet of Things (IoT), there is a growing demand for electric energy in intelligent sensing equipment. Current smart sensors are mostly powered by lithium batteries, and it is necessary to develop a new self-powered device that can replace traditional lithium batteries. This paper designs a maglev electromagnetic-triboelectric hybrid energy converter (METHEC) containing both a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG), which can effectively collect low-frequency vibrational energy. This paper presents a complete device design and optimization system based on theoretical calculation and simulation verification, and establishes a test platform capable of evaluating the dynamic characteristics of METHEC and thus conducts some experiments for validation. In the past, the TENG related to vertical vibration only possessed the test part, and the current was less than 1 mu A, with the power still less than 1 mW even with a large triboelectric area. Additionally, there is no complete research system for devices that utilize vertical vibration. The traditional EMG has a large starting torque, a large volume and can only be applied to higher frequencies, which is not convenient for wide application, and the power rarely exceeds 100 mW. According to this study, excited by the vibrational motion at a frequency of 5.2 Hz, the open-circuit voltages of TENG and EMG are 7.5 V and 9 V, respectively; the short-circuit currents of TENG and EMG are 1.1 mu A and 87.7 mA, respectively; and the maximum power density of TENG reaches 7.5 mW m(-2), while the peak power of EMG reaches 789.3 mW. This paper provides a complete set of innovative exploration systems combining theory, experiment and simulation optimization, which also includes the structural optimization of TENG. METHEC does not require a large starting torque and can also be adapted to low frequencies, and can thus be adapted to more environments. Compared with traditional EMG, METHEC makes it easier to realize the miniaturization of power generation equipment, and according to this research system, other models can be studied expansively.

Ocean buoys are the main equipment for obtaining ocean hydrological information. The lack of efficient and reliable power supply is one of the main technical bottlenecks that limit its long-term stable operation. In this paper, the BUOY-41 surface drifting buoy is taken as an application object, and a novel wave energy converter that can be embedded in the buoy is designed. The novel direct-driven triboelectric–electromagnetic hybridized wave energy converter (DTEWEC) mainly includes triboelectric nanogenerator (TENG) unit and electromagnetic generator (EMG) unit. First, the working principles and basic theories of the two generators were explained. Second, the COMSOL software was used to analyze the influence law of DTEWEC’s main structural parameters on power generation performance, and the optimal structural parameters were preliminarily determined. Then, the STAR-CCM+ software was used to analyze the hydrodynamic characteristics of BUOY-41, and its motion response was input to the above two units. Finally, the performance characteristics of DTEWEC under optimal wave conditions were obtained. The results show that the maximum power density of TENG unit can reach 7.68 W/m2, and the maximum power of each phase of EMG unit which has three-phase coil group structure is 59.4 mW, 47.2 mW, and 50.2 mW, respectively. The research in this paper shows that the DTEWEC can be used as a sustainable power supply component of the ocean buoy to realize the autonomous power supply, which can effectively increase the endurance time and operational reliability.

直接挤出成型制造适用于任何含或不含添加剂的膏状或凝胶状复合材料,对复合材料制造技术具有深远意义.通过探讨热固性环氧树脂的流变学行为与挤出成型特性,得出热固性环氧树脂在直接挤出成型制造应用中的通用性流变学参数.通过向复合材料中加入增稠剂,对其流变学行为进行设计.结果表明:在高剪切速率(50 s-1)和低剪切速率(0.01 s-1)下,添加30％纳米黏土的环氧树脂的流变学行为较适合挤出式3D打印工艺.利用龙门式气动挤出式3D打印机,对复合材料的打印成型质量进行试验分析和验证.结合试验结果探讨了喷头高度对复合材料成型质量的影响,并且提出适用于喷头高度临界值的计算方法.探讨了挤出率、剪切速率等因素对成型质量的作用规律.针对多层打印问题,提出包含补偿系数的多层打印的临界喷头高度的计算方法.以上研究对促进基于复合材料的挤出式3D打印具有积极意义.

飞行器具有零部件多、结构复杂和装配精度要求高等特点,其装配有安全性装配、少可逆性装配等要求.根据飞行器相关的关键产品特性(Key product characteristic,KPC)和关键控制特性(Key control characteristic,KCC)参数,提出一种基于状态空间模型的装配误差敏感度量化分析方法,将飞行器多舱段精密装配过程中的误差敏感度分为3级指标,并进行阐述和定义.通过联立飞行器状态空间模型和输出方程,得到输入向量和输入矩阵的关系,进而求出状态转换矩阵,得到不同级别误差敏感度的理论表达式.将随机产生服从正态分布的装配特征误差代入系统矩阵,运用蒙特卡洛(Monte Carlo)仿真对不同装配特征的敏感度指标进行计算,并对比分析理论计算和蒙特卡洛仿真求得的特征级敏感度指标值.研究表明,将动态系统灵敏度分析方法应用到多工位装配过程可行,所提出的基于状态空间模型的飞行器装配误差敏感度分析方法合理,对飞行器舱段精密装配过程的精度评估具有参考意义.

Small moving vehicles represent an important category of marine engineering tools and devices (equipment) typically used for ocean resource detection and maintenance of marine rights and interests. The lack of efficient power supply modes is one of the technical bottlenecks restricting the effective utilisation of this type of equipment. In this work, the performance characteristics of a new type of elastic-blade/wave-energy converter (EBWEC) and its core energy conversion component (named wave energy absorber) are comprehensively studied. In particular, computational fluid dynamics (CFD) simulations and experiments have been used to analyze the hydrodynamics and performance characteristics of the EBWEC. The pressure cloud diagrams relating to the surface of the elastic blade were obtained through two-way fluid-solid coupling simulations. The influence of blade thickness and relative speed on the performance characteristics of EBWEC was analyzed accordingly. A prototype of the EBWEC and its bucket test platform were also developed. The power characteristics of the EBWEC were analyzed and studied by using the blade thickness and motion cycle as control variables. The present research shows that the EBWEC can effectively overcome the performance disadvantages related to the transmission shaft torque load and power curve fluctuations of rigid blade wave energy converters (RBWEC).

Nowadays, drifters are used for a wide range of applications for researching and exploring the sea. However, the power constraint makes it difficult for their sampling intervals to be smaller, meaning that drifters cannot transmit more accurate measurement data to satellites. Furthermore, due to the power constraint, a modern Surface Velocity Program (SVP) drifter lives an average of 400 days before ceasing transmission. To overcome the power constraint of SVP drifters, this article proposes an adaptively counter-rotating wave energy converter (ACWEC) to supply power for drifters. The ACWEC has the advantages of convenient modular integration, simple conversion process, and minimal affection by the crucial sea environment. This article details the design concept and working principle, and the interaction between the wave energy converter (WEC) and wave is presented based on plane wave theory. To verify the feasibility of the WEC, the research team carried out a series of experiments in a wave tank with regular and irregular waves. Through experiments, it was found that the power and efficiency of the ACWEC are greatly influenced by parameters such as wave height and wave frequency. The maximum output power of the small scale WEC in a wave tank is 6.36 W, which allows drifters to detect ocean data more frequently and continuously.

Marine equipment generally lacks efficient power supply methods. The high energy density of wave energy can facilitate the converter miniaturization and make them easily integrated into marine equipment. This paper presents a novel point energy absorber-type wave energy converter, which is based on the counter-rotating self-adaptable movement mechanism. Comprehensive theoretical analysis, numerical optimization and verification experiments were conducted on its performance characteristics. It was found that the hydrodynamic performances of the WEC are greatly affected by the rotational speed and diameter, and the interaction between the double absorbers is exacerbated by the stabilizing fins.

To solve the real-time problem of edge extraction algorithm and improve image edge continuity, an edge extraction algorithm based on quantum flexible representation (flexible representation of Quantum, RFQ) is proposed. First, the image is represented by quantum flexibility, the superposition state of the quantum sequence is used to store all the pixels of the image, and the FRQ image is obtained by the quantum parallel computation which efficiency is greatly improved, secondly, by the translation transformation of the X and Y directions of the FRQ image, the relative quanta of the neighboring pixels of the whole image is obtained. According to the quantum bit to define the quantum black box U Ω , combining the Sobel operator to compute the Sobel gradient of pixels in order to judge different categories of pixels and extract the edges of the image. The experimental results show that the proposed method has better edge continuity and richer detail edge than the current edge extraction algorithm.

Unmanned marine equipment has been increasingly developed for open seas. The lack of efficient and reliable power supply is currently one of the bottlenecks restricting the practical application of these devices. In order to provide a viable power supply method for unmanned marine equipment, such as sonic buoys and sea robots, we originally propose a novel small-scale flexible blade wave energy converter (WEC) based on self-adaptable counter-rotating operation mechanism. The flexible blade WEC is designed on the basis of the rigid blade WEC with the caging device. This paper identifies the key factors affecting WEC performance through theoretical analysis. According to the numerical simulation analysis, the output mechanical power of the double-layer absorber is 12.8 W, and the hydraulic efficiency is 36.3%. The results of the verification experiment show that the peak power of WEC is 5.8 W and the average power is 3.2 W. The WEC with 65Mn flexible blade under most experimental conditions has the best performance when the blade thickness is 0.10 mm. The study shows that the new generation WEC can effectively overcome the excessive fluctuation of the output power of the previous generation WEC. The output power curve of the novel WEC is relatively smooth, which is conducive to its smooth operation and subsequent utilization and storage of electrical energy.

Long-term energy supplies hinder the application of the low-power unmanned ocean devices to the deep sea. Ocean wave energy is a renewable resource with amount stores of enormous and high density. The wave energy converter (WEC) could be miniaturized so that it can be integrated into the devices to make up the power module. In this paper, a small novel heaving point absorber of energy supply for low-power unmanned ocean devices is developed based on the counter-rotating self-adaptive mechanism. The floating body as an important part of the heaving point absorber, the geometric parameters is optimized to increase the efficiency of power production. Through constructing the constitutive relation between the geometric parameters, the wave force, the motion displacement, the motion velocity, and the capture width ratio of the floating body, the energy efficiency characteristics of the multi-type floating bodies are calculated, and the optimal shape is selected. On the other hand, in the calculation process of the wave force, the Froude-Krylov method is an effective method to accurately calculate the wave excitation force. Meanwhile, nonlinear static and dynamic Froude-Krylov force effectively overcomes the inaccuracy of the linear models and reduces the time consumed to simulate. Finally, the wave force, heaving velocity, heaving displacement, and capture width ratio of the three floating bodies are compared and analyzed, and the results show that the cylindrical floater that is vertically placed on the wave surface is more suitable for the novel heaving wave energy point absorber.

Due to the environmental issues like global warming and pollution, the exploration for ocean energy becomes important. Selecting the suitable generator for wave energy generation system is essential to improve the efficiency of power generation system. Thus, the object of the research is the generator of a self-adaptation inversion type wave energy absorption device. The major focus of this paper is the characteristics and the technique of the generator used in prototype. By setting up the generator performance test platform, the output voltage, efficiency and performance of the generator are tested to select the suitable generator for the wave energy generating system.

With the development of wave energy extraction technology, the performance requirements of wave energy converters have also become higher in order to maximize operating efficiency and the use of wave energy. In this paper, the wave energy characteristics and energy storage characteristics of current common wave energy converters are studied for this demand. Because small-scale wave energy convertors are characterized by their strong mobility and relatively lower power generation, it is not easy to integrate the generated energy directly into the power grid. Therefore, a small, highly efficient and environmentally friendly storage method is needed. Through investigation, the lithium battery pack is used to store the energy output from the convertors by means of a filtered regulated charging circuit.

The current research on the utilization of wave energy has not formed a globally recognized technologically optimal wave energy power generation technology. The various types of wave energy power generation devices have different power generation principles and structural forms. Wave energy has the characteristics of wide distribution and high energy density, but it is also the most unstable type of ocean energy. Compared with other energy sources, wave energy has the characteristics of high energy density, and it is technically easy to realize the miniaturization of equipment, which contributes to the development of ocean resources. This article will mainly introduce current mainstream wave energy technologies, and explore their working principles and analyse their development trends.

The oceans are rich in wave energy that is green energy, and the wave energy are now being used to generate electricity on a massive scale. It can also be used as a single generator for beacon, buoy or underwater vehicle. Micro small wave energy power generation device is a kind of wave energy power generation devices, main characteristic is mobility is good, and can be directly assembled on various kinds of equipment for the power supply, with good prospects for development. The research object of the paper is a new adaptive reversing wave energy generating device belongs to micro-sized wave energy generating device. Using the upper and lower absorber blade groups, the low speed and large torque wave energy can be converted into electric energy which can be used for load and lithium battery charging.

To reduce impact of global warming and the energy crisis problems caused by pollution of energy combustion, the research on renewable and clean energies becomes more and more important.This paper designed a new wave absorption device, and also gave an introduction on its mechanical structure. The flow tube model is analyzed, and presented the formulation of the proposed method. To verify the principle of wave absorbing device, an experiment was carried out in a laboratory environment, and the results of the experiment can be applied for optimizing the structure design of output power.

With the increasing tension of contemporary social energy, the development and utilization of renewable energy has become an important development direction. As an important part of renewable energy, wave energy has the characteristics of green environmental protection and abundant reserves, attracting more investment and research. For small marine equipment energy supply problem, this paper puts forward a micro wave energy conversion device as the basic of heaving motion of waves in the ocean. This paper designed a new type of power output device can solve the micro wave energy conversion problem.