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574 results on '"Meng, Xiaoyu"'

4. Associations of physiologic subtypes based on HOMA2 indices of β-cell function and insulin sensitivity with the risk of kidney function decline, cardiovascular disease, and all-cause mortality from the 4C study

Author

Luo, Peiqiong, Li, Danpei, Guo, Yaming, Meng, Xiaoyu, Kan, Ranran, Pan, Limeng, Xiang, Yuxi, Mao, Beibei, He, Yi, Wang, Siyi, Yang, Yan, Liu, Zhelong, Xie, Junhui, Zhang, Benping, He, Wentao, Hu, Shuhong, Zhou, Xinrong, and Yu, Xuefeng

Published
2024
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20. Integrated intelligent Jaya Runge-Kutta method for solving Falkner-Skan equations for Various Wedge Angles

Author

Guo, Hongwei, Zhuang, Xiaoying, Meng, Xiaoyu, and Rabczuk, Timon

Subjects
Mathematics - Numerical Analysis, Computer Science - Networking and Internet Architecture, Physics - Computational Physics
Abstract

In this work, the hybrid intelligent computing method, which combines efficient Jaya algorithm with classical Runge-Kutta method is applied to solve the Falkner-Skan equations with various wedge angles, which is the fundamental equation for a variety of computational fluid mechanical problems. With some coordinate transformation, the Falkner-Skan boundary layer problem is then converted into a free boundary problem defined on a finite interval. Then using higher order reduction strategies, the whole problem can be boiled down to a solving of coupled differential equations with prescribed initial and boundary conditions. The hybrid Jaya Runge-Kutta method is found to yield stable and accurate results and able to extract those unknown parameters. The sensitivity of classical shooting method to the guess of initial values can be easily overcome by an integrated robust optimization method. In addition, the Jaya algorithm, without the need for tuning the algorithm-specific parameters, is proved to be effective and stable for minimizing the fitness function in application. By comparing the solutions using the Jaya method with PSO (particle swarm optimization), Genetic algorithm (GA), Hyperband, and the classical analytical methods, the hybrid Jaya Runge-Kutta method yields more stable and accurate results, which shows great potential for solving more complicated multi-field and multiphase flow problems.

Published
2020

21. Remote Sensing-Based Detection of Vegetation Cover Change in Govi-Sumber Province, Mongolia

Author

Davaanyam, Otgontsetseg, Otgon, Ishtsog, Tsetsegmaa, Ganchudur, Meng, Xiaoyu, Akhmadi, Khaulenbek, Chan, Albert P. C., Series Editor, Hong, Wei-Chiang, Series Editor, Mellal, Mohamed Arezki, Series Editor, Narayanan, Ramadas, Series Editor, Nguyen, Quang Ngoc, Series Editor, Ong, Hwai Chyuan, Series Editor, Sachsenmeier, Peter, Series Editor, Sun, Zaicheng, Series Editor, Ullah, Sharif, Series Editor, Wu, Junwei, Series Editor, Zhang, Wei, Series Editor, Batdelger, Odsuren, editor, Damdinsuren, Amarsaikhan, editor, Avirmed, Dashtseren, editor, and Erdenee, Bolortsetseg, editor

Published
2023
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49. Study on the Fluid-Solid Coupling Seepage of the Deep Tight Reservoir Based on 3D Digital Core Modeling.

Author

Yang, Haijun, Cai, Zhenzhong, Zhang, Hui, Sun, Chong, Li, Jing, Meng, Xiaoyu, Liu, Chen, and Yang, Chengqiang

Subjects
PERMEABILITY measurement, SANDSTONE, HYDRAULIC conductivity, GEOLOGICAL modeling, HYDRAULIC couplings
Abstract

Deep tight reservoirs exhibit complex stress and seepage fields due to varying pore structures, thus the seepage characteristics are significant for enhancing oil production. This study conducted triaxial compression and permeability tests to investigate the mechanical and seepage properties of tight sandstone. A digital core of tight sandstone was built using Computed Tomography (CT) scanning, which was divided into matrix and pore phases by a pore equivalent diameter threshold. A fluid-solid coupling model was established to investigate the seepage characteristics at micro-scale. The results showed that increasing the confining pressure decreased porosity, permeability, and flow velocity, with the pore phase becoming the dominant seepage channel. Cracks and large pores closed first under increasing pressure, resulted in a steep drop in permeability. However, permeability slightly decreased under high confining pressure, which followed a first-order exponential function. Flow velocity increased with seepage pressure. And the damage mainly occurred in stress-concentration regions under low seepage pressure. Seepage behavior followed linear Darcy flow, the damage emerged at seepage entrances under high pressure, which decreased rock elastic modulus and significantly increased permeability. [ABSTRACT FROM AUTHOR]

Published
2025
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50. A Study on the Residual Oil Distribution in Tight Reservoirs Based on a 3D Pore Structure Model.

Author

Wang, Rujun, Zhang, Yintao, Sun, Chong, Li, Jing, Meng, Xiaoyu, Yang, Chengqiang, and Chen, Zhaoyang

Subjects
PETROLEUM distribution, POROSITY, WATER distribution, ADSORPTION capacity, COMPUTED tomography
Abstract

A tight reservoir is characterized by low porosity and permeability as well as a complex pore structure, resulting in low oil recovery efficiency. Understanding the micro-scale distribution of residual oil is of great significance for improving oil production and water flooding recovery rates. In this study, a 3D pore structure model of tight sandstone was established using CT scanning to characterize the residual oil distribution after water flooding. The effects of displacement methods and wettability on residual oil distribution at the micro-scale were then studied and discussed. Moreover, increasing the displacement rate has little effect on the distribution area and dominant seepage channels. Microscopic residual oil is classified into five discontinuous phases according to the oil–water–pore–throat contact relationship. The microscopic residual oil exhibits characteristics of being dispersed overall but locally concentrated. Under water-wet conditions, the injected water tends to strip the oil phase along the pore walls. Under oil-wet conditions, the pore walls have an improved adsorption capacity for the oil phase, resulting in a large amount of porous and membranous residual oil retained in the pores, which leads to a decrease in the overall recovery rate. [ABSTRACT FROM AUTHOR]

Published
2025
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