Open Access
EDITORIAL
Qian Yin1,2,3, Yujing Jiang2,3,*, Richeng Liu1,3
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 437-441, 2021, DOI:10.32604/cmes.2021.015432
（This article belongs to this Special Issue: Modeling and Simulation of Fluid flows in Fractured Porous Media: Current Trends and Prospects)
Abstract This article has no abstract. More >
Open Access
ARTICLE
Hongwei Zhang1,2, Zhijun Wan3, Yixin Zhao1,2, Yuan Zhang3, Yulong Chen2,*, Junhui Wang3,*, Jingyi Cheng3
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 443-455, 2021, DOI:10.32604/cmes.2021.013179
（This article belongs to this Special Issue: Modeling and Simulation of Fluid flows in Fractured Porous Media: Current Trends and Prospects)
Abstract In the enhanced geothermal system (EGS), the injected fluid will induce shear sliding of rock fractures (i.e.,
hydroshearing), which consequently, would increase the fracture aperture and improve the heat transfer efficiency
of the geothermal reservoir. In this study, theoretical analysis, experimental research and numerical simulation
were performed to uncover the permeability and heat transfer enhancement mechanism of the Hot-Dry-Rock
(HDR) mass under the impact of shearing. By conducting the direct shear test with the fractured rock samples,
the evolution process of fracture aperture during the shearing tests was observed, during which process, cubic law
was adopted to depict the rock… More >
Open Access
ARTICLE
Tantan Zhu*, Yao Li
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 457-477, 2021, DOI:10.32604/cmes.2021.014284
（This article belongs to this Special Issue: Modeling and Simulation of Fluid flows in Fractured Porous Media: Current Trends and Prospects)
Abstract Punch shear tests have been widely used to determine rock shear mechanical properties but without a standard sample geometric dimension suggestion. To investigate the impacts of sample geometric dimensions on shear behaviors in a punch shear test, simulations using Particle Flow Code were carried out. The effects of three geometric dimensions (i.e., disk diameter, ratio of shear surface diameter to disk diameter, and ratio of disk height to shear surface diameter) were discussed. Variations of shear strength, shear stiffness, and shear dilatancy angles were studied, and the fracture processes and patterns of samples were investigated. Then, normal stress on the… More >
Open Access
ARTICLE
Liqun Wang1, Zengtao Chen2, Guolai Yang1,*
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 479-503, 2021, DOI:10.32604/cmes.2021.011954
Abstract This paper proposes a non-intrusive uncertainty analysis method for artillery dynamics involving hybrid uncertainty using polynomial chaos expansion (PCE). The uncertainty parameters with sufficient information are regarded as stochastic variables, whereas the interval variables are used to treat the uncertainty parameters with limited stochastic knowledge. In this method, the PCE model is constructed through the Galerkin projection method, in which the sparse grid strategy is used to generate the integral points and the corresponding integral weights. Through the sampling in PCE, the original dynamic systems with hybrid stochastic and interval parameters can be transformed into deterministic dynamic systems, without changing… More >
Open Access
ARTICLE
Ankit Kumar, Balram Dubey*
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 505-547, 2021, DOI:10.32604/cmes.2021.013206
Abstract In this paper, the impact of additional food and two discrete delays on the dynamics of a prey-predator model is investigated. The interaction between prey and predator is considered as Holling Type-II functional response. The additional food is provided to the predator to reduce its dependency on the prey. One delay is the gestation delay in predator while the other delay is the delay in supplying the additional food to predators. The positivity, boundedness and persistence of the solutions of the system are studied to show the system as biologically well-behaved. The existence of steady states, their local and global… More >
Open Access
ARTICLE
Yi Ji1,2, Yufeng Xing1,*
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 549-575, 2021, DOI:10.32604/cmes.2021.014244
Abstract Based on the weighted residual method, a single-step time integration algorithm with higher-order accuracy and
unconditional stability has been proposed, which is superior to the second-order accurate algorithms in tracking
long-term dynamics. For improving such a higher-order accurate algorithm, this paper proposes a two sub-step
higher-order algorithm with unconditional stability and controllable dissipation. In the proposed algorithm, a time
step interval [tk, tk + h] where h stands for the size of a time step is divided into two sub-steps [tk, tk + γh] and
[tk + γh, tk + h]. A non-dissipative fourth-order algorithm is used in the rst… More >
Open Access
ARTICLE
Weidong Lei1, Hai Zhou1,*, Hongjun Li2, Rui Chen1
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 577-597, 2021, DOI:10.32604/cmes.2021.011857
Abstract In order to simulate the propagation process of subway vibration of parallel tunnels in semi-infinite rocks or
soils, time domain boundary element method (TD-BEM) formulation for analyzing the dynamic response of
twin-parallel circular tunnels in an elastic semi-infinite medium is developed in this paper. The time domain
boundary integral equations of displacement and stress for the elastodynamic problem are presented based on
Betti’s reciprocal work theorem, ignoring contributions from initial conditions and body forces. In the process of
establishing time domain boundary integral equations, some virtual boundaries are constructed between finite
boundaries and the free boundary to form a boundary… More >
Open Access
ARTICLE
T. K. Sreelakshmi1, Abraham Annamma1, A. S. Chethan1, M. Krishna Murthy2, C. S. K. Raju3,*
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 599-616, 2021, DOI:10.32604/cmes.2021.013077
Abstract The current article discusses the heat transfer characteristics of
ferromagnetic liquid over an elastic surface with the thermal radiation and
non-Fourier heat flux. In most of the existing studies, the heat flux is considered as constant, but whereas we incorporated the non-Fourier flux to get the
exact performance of the flow. Also, we excluded the PWT and PHF cases
to control the boundary layer of the flow. The governing equations related to
our contemplate are changed into non-linear ordinary differential equations
(ODE’s) by utilizing appropriate similarity changes, which are at the point
enlightened by Runge–Kutta based shooting approach. The equations… More >
Open Access
ARTICLE
Jian Ma1,2, Changxuan Wen3, Chen Zhang2,*
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 617-644, 2021, DOI:10.32604/cmes.2021.014474
Abstract High-specific-impulse electric propulsion technology is promising for future space robotic debris removal in sun-synchronous orbits. Such a prospect involves solving a class of challenging problems of low-thrust orbital rendezvous between an active spacecraft and a free-flying debris. This study focuses on computing optimal low-thrust minimum-time many-revolution trajectories, considering the effects of the Earth oblateness perturbations and null thrust in Earth shadow. Firstly, a set of mean-element orbital dynamic equations of a chaser (spacecraft) and a target (debris) are derived by using the orbital averaging technique, and specifically a slow-changing state of the mean longitude difference is proposed to accommodate to… More >
Open Access
Xu Li1, Ying Yan2, Shuai Shao3, Shunying Ji1,*
CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 645-671, 2021, DOI:10.32604/cmes.2021.013674
Abstract Considering the interaction between a sleeper, ballast layer, and substructure, a three-dimensional coupled discrete-finite element method for a ballasted railway track is proposed in this study. Ballast granules with irregular shapes are constructed using a clump model using the discrete element method. Meanwhile, concrete sleepers, embankments, and foundations are modelled using 20-node hexahedron solid elements using the finite element method. To improve computational efficiency, a GPU-based (Graphics Processing Unit) parallel framework is applied in the discrete element simulation. Additionally, an algorithm containing contact search and transfer parameters at the contact interface of discrete particles and finite elements is developed in… More >
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