Yiguo Chen^1,2,3,*, Congjun Feng^1,2, Yonghong He³, Zhijun Chen³, Xiaowei Fan³, Chao Wang³, Xinmin Ge⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.3, pp. 2451-2463, 2023, DOI:10.32604/cmes.2023.021145

Abstract The low-field nuclear magnetic resonance (NMR) technique has been used to probe the pore size distribution and the fluid composition in geophysical prospecting and related fields. However, the speed and accuracy of the existing numerical inversion methods are still challenging due to the ill-posed nature of the first kind Fredholm integral equation and the contamination of the noises. This paper proposes a novel inversion algorithm to accelerate the convergence and enhance the precision using empirical truncated singular value decompositions (TSVD) and the linearized Bregman iteration. The L1 penalty term is applied to construct the objective function, and then the linearized… More > Graphic Abstract

Yanju Wang¹, Zhenyu Zhu², Aixue Sha¹, Wenfeng Hao^3,*

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.3, pp. 2655-2676, 2023, DOI:10.32604/cmes.2023.025749

Abstract Many titanium alloy subcomponents are subjected to fatigue loading in aerospace engineering, resulting in fatigue failure. The fatigue behavior of Ti₂AlNb alloy subcomponents was investigated based on the Seeger fatigue life theory and the improved Lemaitre damage evolution theory. Firstly, the finite element models of the standard openhole specimen and Y-section subcomponents have been established by ABAQUS. The damage model parameters were determined by fatigue tests, and the reliability of fatigue life simulation results of the Ti₂AlNb alloy standard open-hole specimen was verified. Meanwhile, the fatigue life of Ti₂AlNb alloy Y-section subcomponents was predicted. Under the same initial conditions, the… More >

Ningbo Guo, Xianming Gao^*, Duanling Li, Jixing Zhang, Penghui Yin, Mengyi Hua

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.3, pp. 3061-3082, 2023, DOI:10.32604/cmes.2023.026657

Abstract Computational fluid dynamics was used and a numerical simulation analysis of boiling heat transfer in microchannels with three depths and three cross-sectional profiles was conducted. The heat transfer coefficient and bubble generation process of three microchannel structures with a width of 80 μm and a depth of 40, 60, and 80 μm were compared during the boiling process, and the factors influencing bubble generation were studied. A visual test bench was built, and test substrates of different sizes were prepared using a micro-nano laser. During the test, the behavior characteristics of the bubbles on the boiling surface and the temperature… More >

Hongsha Xiao¹, Ruihan Zhang^2,*, Man Chen¹, Cui Jing¹, Shangjun Gao¹, Chao Chen¹, Huiyan Zhao¹, Xin Huang^2,*, Bo Kang³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.7, pp. 1803-1815, 2023, DOI:10.32604/fdmp.2023.026143

Abstract The production performances of a well with a shale gas reservoir displaying a complex fracture network are simulated. In particular, a micro-seismic cloud diagram is used to describe the fracture network, and accordingly, a production model is introduced based on a multi-scale flow mechanism. A finite volume method is then exploited for the integration of the model equations. The effects of apparent permeability, conductivity, Langmuir volume, and bottom hole pressure on gas well production are studied accordingly. The simulation results show that ignoring the micro-scale flow mechanism of the shale gas leads to underestimating the well gas production. It is… More > Graphic Abstract

Romana Basit¹, Xinyang Li¹, Zheqing Huang¹, Qiang Zhou^1,2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.2, pp. 1509-1526, 2023, DOI:10.32604/cmes.2023.025308

Abstract Direct Numerical Simulations have been carried out to study the forced convection heat transfer of flow through fixed prolate particles for a variety of aspect ratios ar = {5/4, 5/3, 5/1} with Reynolds number (Re) up to 100. Three variations of the solid volume fraction c = {0.1, 0.2, 0.3} with four Hermans orientation factors S = {−0.5, 0, 0.5, 1} are studied. It has been found that changes in S cause prominent variations in the Nusselt number. In general, Nusselt number increases with the decrease of S. For all three aspect ratios, the Nusselt number remains a linear function… More > Graphic Abstract

Ying Wang^*, Zheng Yan, Yangyang Wu

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.2, pp. 1339-1370, 2023, DOI:10.32604/cmes.2023.025830

Abstract In this paper, a numerical model of fretting fatigue analysis of cable wire and the fretting fatigue damage constitutive model considering the multi-axis effect were established, and the user material subroutine UMAT was written. Then, the constitutive model of wear morphology evolution of cable wire and the constitutive model of pitting evolution considering the mechanical-electrochemical effect were established, respectively. The corresponding subroutines UMESHMOTION_Wear and UMESHMOTION_Wear_Corrosion were written, and the fretting fatigue life was further predicted. The results show that the numerical simulation life obtained by the program in this paper has the same trend as the tested one; the error… More > Graphic Abstract

Changrong Zhang, Hongtao Guo, Li Yu, Binbin Lv, Hongya Xia^*

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.2, pp. 1743-1758, 2023, DOI:10.32604/cmes.2023.025528

Abstract This study presents a high-speed geometrically nonlinear flutter analysis calculation method based on the high-precision computational fluid dynamics/computational structural dynamics methods. In the proposed method, the aerodynamic simulation was conducted based on computational fluid dynamics, and the structural model was established using the nonlinear finite element model and tangential stiffness matrix. First, the equilibrium position was obtained using the nonlinear static aeroelastic iteration. Second, the structural modal under a steady aerodynamic load was extracted. Finally, the generalized displacement time curve was obtained by coupling the unsteady aerodynamics and linearized structure motion equations. Moreover, if the flutter is not at a… More > Graphic Abstract

Xiaohui Cheng¹, Haiqing Si^1,*, Yao Li¹, Peihong Zhang²

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.2, pp. 1729-1742, 2023, DOI:10.32604/cmes.2023.022694

Abstract To understand the influence of the initial release conditions on the separation characteristics of the store and improve it under high Mach number (Ma = 4) flight conditions, the overset grid method and the Realizable turbulence model coupled with an equation with six degrees of freedom are used to simulate the store released from the internal bay. The motion trajectory and the attitude angle of the store separation under the conditions of different centroid, velocity, height and control measures are given by the calculated result. Through analysis, the position of the centroid will affect the separation of the store, which needs to… More >

Weiting Jiang^*, Tingni He^*, Chongyang Wang, Weiguo Pan, Jiang Liu

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.6, pp. 1447-1461, 2023, DOI:10.32604/fdmp.2023.025269

Abstract Computational Fluid Dynamics (CFD) is used here to reduce pressure loss and improve heat exchange efficiency in the recuperator associated with a gas turbine. First, numerical simulations of the high-temperature and low-temperature channels are performed and, the calculated results are compared with experimental data (to verify the reliability of the numerical method). Second, the flow field structure of the low-temperature side channel is critically analyzed, leading to the conclusion that the flow velocity distribution in the low-temperature side channel is uneven, and its resistance is significantly higher than that in the high-temperature side. Therefore, five alternate structural schemes are proposed… More > Graphic Abstract

Liang Yang^*, Tianle Xi, Zhixing Wang

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.6, pp. 1585-1608, 2023, DOI:10.32604/fdmp.2023.024987

Abstract The VOF method is used to simulate the dynamics of a droplet interacting with a structure consisting of an array of microcolumns mounted on a flat surface. Such a specific configuration is intended to mimic the typical properties of lotus leaves, which typically display regularly arranged micron-scale papillary structures. After setting the initial velocity of the simulated droplet on the basis of practical considerations, an analysis is conducted about the effect of the characteristic size of the microstructure on the apparent contact angle. The pressure variation in the microstructure caves is also examined. The simulation results show that the change… More >