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Yuanyao Zhu

Bio: Yuanyao Zhu is an academic researcher. The author has contributed to research in topics: Electrical engineering & Computational fluid dynamics. The author has an hindex of 1, co-authored 6 publications receiving 6 citations.

Papers
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TL;DR: In this paper , the authors used the Taguchi method to optimize the typical parameters of the vertical axis turbine, i.e., airfoil (NACA), pitch angle (β), enwinding ratio (ϖ), solidity ratio (σ), and small shaft position (O).

6 citations

Journal ArticleDOI
TL;DR: In this article , the authors established a model of a semi-submersible platform and a flexible mooring system in a numerical pool by means of the computational fluid dynamics (CFD) method.
Abstract: Semi-submersible offshore platforms play a vital role in deep-sea energy exploitation. However, the vast waves threaten the platform’s operation, usually leading to severe consequences. It is essential to study the wave-slamming mechanism of offshore platforms under extreme wave conditions. Existing research usually simplifies the offshore platform slamming problem. This paper establishes a model of a semi-submersible platform and a flexible mooring system in a numerical pool by means of the computational fluid dynamics (CFD) method. The distribution and the sensitivity of the slamming load on columns and deck in waves were investigated, and the model was verified through the basin test. Firstly, based on the Reynolds-averaged Navier–Stokes model, this study considers the volume-of-fluid method to track the free liquid level. After the column and floating body grid are locally refined, the slamming load under extreme regular wave impact is measured by measuring points on the column and deck. Then, the slamming experiment of the semi-submersible was carried out in the basin. The experiment model with a scale ratio of 1:100 was established to investigate the platform’s motion and slamming loads under extreme regular and irregular waves. The findings indicate that the slamming load at the junction of the column and deck significantly increased, exhibiting a ‘double-peak’ phenomenon at the middle of the column. The maximum pressure of slamming at the top of the column demonstrated an inverted U-shaped distribution, with negative pressure occurring after the peak value, indicating a pronounced oscillation effect.
Journal ArticleDOI
TL;DR: In this paper , a rotating tower-like triboelectric nanogenerator (RT-TENG) with an innovative circuit which combine discharge tube (DT) with voltage boost circuit (D-VBC) is proposed for ultrahigh charge density breakthrough.

Cited by
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Journal ArticleDOI
02 Aug 2022-Energies
TL;DR: In this article , a drag-lift hybrid type wind turbine structure based on an NACA0018 symmetrical airfoil was proposed, which can adaptively change the blade shape under static and low speed conditions.
Abstract: In recent years, with the continuous development of new energy, how to efficiently use wind energy has received more and more market attention. Due to cost advantages, the development of small wind turbines is accelerating. Among them, the design and research of the airfoil design and research of the lift vertical axis wind turbine has matured, but because of the aerodynamic characteristics of the lift airfoil structure, it is impossible to start itself at low wind speed, resulting in the waste of low wind speed energy. Although the drag wind turbine has good self-starting performance, the wind energy utilization efficiency in the high-speed state is inefficient. Each has its own unique shortcomings, which directly affects the marketization of small wind turbines. In order to solve these problems, this paper presents a drag-lift hybrid type wind turbine structure based on an NACA0018 symmetrical airfoil, which can adaptively change the blade shape. This design can keep the blade in the drag shape under static and low speed conditions, and adaptively change the lift shape with the increase of speed. In addition, through the research method of CFD numerical simulation combined with physical experiments, the proposed wind turbine design is studied and analyzed from multiple angles. At the same time, the “6DOF + dynamic grid” setting is used to study the influence of the opening angle factor of the drag-lift hybrid blade on the self-starting performance, and the study shows that the design of the drag-lift hybrid blade proposed in this paper has a higher self-starting torque and lower starting wind speed than the traditional lifting blade, and it is observed that the drag-lift hybrid blade has the best self-starting performance when the opening angle of the blade is 80°. At the same time, the problem of switching the blade morphology of the drag-lift hybrid blade is also analyzed, along with how to use the spring to control all this adaptively. In order to better analyze the advantages of the drag-lift hybrid design proposed in this paper, a wind tunnel test was also carried out using the physical model, and the relationship between the leaf tip speed ratio and the wind energy utilization rate was obtained, which intuitively showed the improvement of the wind energy utilization rate of the drag-lift hybrid design compared with the traditional lift blade.

2 citations

Journal ArticleDOI
TL;DR: In this paper , two surrogate models, i.e., Kriging and artificial neural networks (ANN), were adopted for the performance prediction of a twin-VAWT with a close staggered arrangement.

2 citations

Journal ArticleDOI
TL;DR: In this article , the performance comparison of straight and helical-bladed lift-based VAHTs and the influence of design and operating conditional parameters was made and the potential research areas that need to be addressed in future studies were also found and presented.

2 citations

Journal ArticleDOI
TL;DR: In this article , an orthogonal array outlining these five parameters, e.g., spacing (L/D), rotation direction (RD), phase difference (ϕ), incoming flow angle (β), and blade-tip speed ratio (λ), with 4 different levels per parameter, is constructed.
TL;DR: In this article , the effects of turbulence on power generation from a current energy converter (CEC) are not fully understood and the authors investigated the correlation between a vertical axis CEC's power output and the water velocity in the frequency and time domains.
Abstract: The effects of turbulence on power generation from a Current Energy Converter (CEC) are not fully understood. This thesis investigates the correlation between a vertical axis CEC's power output and the water velocity in the frequency and time domains. Chapter 2 shows the correlation between velocity and electrical power in frequency space. This correlation gives insight into the size of eddies that influence the CEC's power output. The results of this correlation analysis show that eddies of diameter around 0.8m have a noticeable impact on the power generation. Calculating the observed average integral length scale, the range of eddy diameters around the CEC are 0.52m-5.8m. Since 0.8m is in this observed range it suggests that the turbulence may influence the CEC's power output. Chapter 3 analyzes the relationship between the turbulence velocity cubed and electrical power through the correlation of the two data sets. The correlation was carried out by first separating out the four velocity components derived from cubing the sum of the turbulence and average velocities. The commonly used ratio of the turbulence kinetic energy to total kinetic energy does not include these cross terms nor are these cross terms typically included in the calculation of power derived from the turbulence velocity. The turbulence velocity cubed has a correlation of -0.007 with the CEC power output indicating that the turbulence has a small, negative impact on the CEC power output.