Fengxia Shi^1,2, Guangbiao Zhao^1,*, Yucai Tang¹, Dedong Ma¹, Xiangyun Shi¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.11, pp. 2617-2636, 2024, DOI:10.32604/fdmp.2024.053186 - 28 October 2024

Abstract To analyze the effect of blade number on the performance of hydraulic turbines during the transient stage in which the flow rate is not constant, six hydraulic turbines with different blade numbers are considered. The instantaneous hydraulic performance of the turbine and the pressure pulsation acting on the impeller are investigated numerically by using the ANSYS CFX software. The ensuing results are compared with the outcomes of experimental tests. It is shown that the fluctuation range of the pressure coefficient increases with time, but the corresponding range for the transient hydraulic efficiency decreases gradually when… More >

Haoming Mo^1,*, Junhao Ding¹, Xu Song¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.011375

Abstract Triply periodic minimal surface (TPMS) shell-lattices are attracting increasing attention because of their exceptional mechanical and geometric characteristics. Additive manufactured TPMS structures using thermoplastic polyurethane (TPU) have great application potential in energy absorptions, for which the mechanical properties can be conveniently adjusted to meet diverse requirements. Nevertheless, there is a need for further improvement in the stability and adjustability of energy absorption capacity. This is due to the significant impact of the buckling effect and induced stress fluctuations when the structure is subjected to compression. To alleviate the buckling effect and tune the capability of… More >

Tiantian Yu¹, Youping Lv¹, Hao Zhong², Ming Liu¹, Pingyuan Gai¹, Zeju Jiang¹, Peng Zhang¹, Xingkai Zhang^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.8, pp. 1759-1772, 2024, DOI:10.32604/fdmp.2024.049035 - 06 August 2024

Abstract A new measurement device, consisting of swirling blades and capsule-shaped throttling elements, is proposed in this study to eliminate typical measurement errors caused by complex flow patterns in gas-liquid flow. The swirling blades are used to transform the complex flow pattern into a forced annular flow. Drawing on the research of existing blockage flow meters and also exploiting the single-phase flow measurement theory, a formula is introduced to measure the phase-separated flow of gas and liquid. The formula requires the pressure ratio, Lockhart-Martinelli number (L-M number), and the gas phase Froude number. The unknown parameters More >

Fengxia Shi^1,2, Guangbiao Zhao^1,*, Yucai Tang¹, Haonan Zhan¹, Pengcheng Wang¹

Sound & Vibration, Vol.58, pp. 101-117, 2024, DOI:10.32604/sv.2024.047082 - 11 March 2024

Abstract In order to study the effect of splitter blades on the internal and external sound field of the hydraulic turbine, the paper chose a centrifugal pump with a specific speed n_s = 33 reversed as a hydraulic turbine as the research object, and added the short blades on the original impeller to form a new splitter impeller. Based on the Re-Normalization Group (RNG) k-ε turbulence model to conduct numerical simulation for the hydraulic turbine, this thesis calculated the internal and external acoustic field by means of the acoustic boundary element (BEM) and finite element (FEM) and… More >

Yujie Duan¹, Jianguo Liang^1,*, Jianglin Liu¹, Haifeng Gao¹, Yinhui Li², Jinzhu Zhang¹, Xinyu Wen³

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.2, pp. 1239-1261, 2024, DOI:10.32604/cmes.2023.044400 - 29 January 2024

Abstract In the fiber winding process, strong disturbance, uncertainty, strong coupling, and fiber friction complicate the winding constant tension control. In order to effectively reduce the influence of these problems on the tension output, this paper proposed a tension fluctuation rejection strategy based on feedforward compensation. In addition to the bias harmonic curve of the unknown state, the tension fluctuation also contains the influence of bounded noise. A tension fluctuation observer (TFO) is designed to cancel the uncertain periodic signal, in which the frequency generator is used to estimate the critical parameter information. Then, the fluctuation More >

Zixiong Wang, Qiuying Chen, Sang-Joon Lee^*

CMC-Computers, Materials & Continua, Vol.75, No.2, pp. 2443-2459, 2023, DOI:10.32604/cmc.2023.037553 - 31 March 2023

Abstract The rapid expansion of the non-fungible token (NFT) market has attracted many investors. However, studies on the NFT price fluctuations have been relatively limited. To date, the machine learning approach has not been used to demonstrate a specific error in NFT sale price fluctuation prediction. The aim of this study was to develop a prediction model for NFT price fluctuations using the NFT trading information obtained from OpenSea, the world’s largest NFT marketplace. We used Python programs to collect data and summarized them as: NFT information, collection information, and related account information. AdaBoost and Random… More >

L. Cheng^a , Y. L. Zhang^a,† , J. F. Li^b

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-7, 2022, DOI:10.5098/hmt.19.32

Abstract The internal characteristics during rotational speed fluctuation have an important influence on centrifugal pump to avoid or utilize its transient performance. In this paper, a circulation piping system that includes a low-specific-speed centrifugal pump is established to study the energy distribution characteristics in a centrifugal pump during speed fluctuation. The unsteady flow in the entire system is numerically calculated with a user-defined function, the sliding grid method, and the RNG k-ε turbulence model. Then, the energy distribution of the transient flow field in the centrifugal pump model during speed fluctuation is diagnosed with vortex dynamics More >

Guodong Liu^1,2,*, Zhijun Zhou¹, Shiqiang Xu¹, Wenjing Mi²

CMES-Computer Modeling in Engineering & Sciences, Vol.133, No.2, pp. 351-375, 2022, DOI:10.32604/cmes.2022.020335 - 21 July 2022

Abstract Water level variations have caused numerous dam slope collapse disasters around the world, illustrating the large influence of water level fluctuations on dam slopes. The required indoor tests were conducted and a numerical model of an actual earth-filled dam was constructed to investigate the influences of the water level fluctuation rate and the hysteresis of the soil–water characteristic curve (SWCC) on the stability of the upstream dam slope. The results revealed that the free surface in the dam body for the desorption SWCC during water level fluctuations was higher than that for the adsorption SWCC, More >

Magdalini Ntetsika, Panayiotis Papadopoulos^*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1243-1258, 2021, DOI:10.32604/cmes.2021.017404 - 25 November 2021

Abstract A new and computationally efficient version of the immersed boundary method, which is combined with the coarse-graining method, is introduced for modeling inextensible filaments immersed in low-Reynolds number flows. This is used to represent actin biopolymers, which are constituent elements of the cytoskeleton, a complex network-like structure that plays a fundamental role in shape morphology. An extension of the traditional immersed boundary method to include a stochastic stress tensor is also proposed in order to model the thermal fluctuations in the fluid at smaller scales. By way of validation, the response of a single, massless, More >

Emad H. El-Zohri¹, Hegazy Rezk^2,3,*, Basem Alamri⁴, Hamdy A. Ziedan⁵

Intelligent Automation & Soft Computing, Vol.30, No.1, pp. 201-213, 2021, DOI:10.32604/iasc.2021.018700 - 26 July 2021

Abstract Microgrids are hybrid power systems that consist of several distributed generation resources and local loads that can supply electrical power to remote or specific areas. The integration of microgrids with the utility network is one of the most recent technologies developed in countries like Egypt. One area of study is how the integration of smart microgrids and utility systems can be used to solve power quality problems such as voltage sags, increased use of distributed generators, deep energy, and power loss. This paper is aimed at investigating a possible solution to some common and dangerous… More >