Yong Guan¹, Wanling Hu^{1, 2, *}, Yun Zhang¹, Kewei Song^{2, 3}, Liangbi Wang^{2, 3}

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 237-256, 2020, DOI:10.32604/cmes.2020.09141

Abstract The application of vortex generators in tube-finned heat exchangers is very universal. The vortex generators can generate secondary flow, and as we all know secondary flow can obviously strengthen heat transfer. To use vortex generators much more efficiently in the circle tube-finned heat exchangers, the intensity correlation study between secondary flow and heat transfer is needed. 22 different structures of circle tubefinned heat exchangers were numerically studied, including the plain fin cases and the cases with vortex generators. In addition, the influence of fin spacing, transverse and longitudinal tube pitch, heights and attack angle of vortex generators, positions of vortex… More >

Shuifen Zhan^{1, 2, 3}, Mingchao Wang^{2, *}, Min Wang^{5, *}, Qianqian Shao⁴, Zefang Zhang³, Wenxin Jiang², Xuemin Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 217-235, 2020, DOI:10.32604/cmes.2020.08289

Abstract Considering the accidents of ships for dangerous chemicals transportation in inland rivers, a numerical method for the simulation of the leakage and diffusion processes of dangerous chemicals in inland rivers is proposed in this paper. Geographic information, such as rivers and buildings in the model, is obtained through Google Earth and structures of rivers and buildings are described by Auto CAD. In addition, the Fluent is adopted to simulate the leakage and diffusion processes of the dangerous chemicals where the standard k-ε model is used to calculate the turbulent flow. Considering the interaction between chemicals and water, the VOF method… More >

Xiaofeng Yang^{1, *}, Yanhong Li¹, Aiguo Nie¹, Sheng Zhi², Liyuan Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.3, pp. 1141-1157, 2020, DOI:10.32604/cmes.2020.08538

Abstract Supercritical carbon dioxide (Sc-CO₂) jet rock breaking is a nonlinear impact dynamics problem involving many factors. Considering the complexity of the physical properties of the Sc-CO₂ jet and the mesh distortion problem in dealing with large deformation problems using the finite element method, the smoothed particle hydrodynamics (SPH) method is used to simulate and analyze the rock breaking process by Sc-CO₂ jet based on the derivation of the jet velocity-density evolution mathematical model. The results indicate that there exisits an optimal rock breaking temperature by Sc-CO₂. The volume and length of the rock fracture increase with the rising of the… More >

Haiqing Li¹, Mengge Yu^{1, *}, Qian Zhang¹, Heng Wen¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 77-90, 2020, DOI:10.32604/fdmp.2020.07797

Abstract The performances of high-speed trains in the presence of coupling effects with crosswind and rain have attracted great attention in recent years. The objective of the present paper was to investigate the aerodynamic characteristics of a high-speed train under such conditions in the framework of an Eulerian-Lagrangian approach. An aerodynamic model of a high-speed train was first set up, and the side force coefficient obtained from numerical simulation was compared with that provided by wind tunnel experiments to verify the accuracy of the approach. Then, the effects of the yaw angle, the resultant wind speed, and the rainfall rate on… More >

Zhiyuan Dai¹, Tian Li^{1, *}, Weihua Zhang¹, Jiye Zhang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 31-40, 2020, DOI:10.32604/fdmp.2020.07661

Abstract Pantograph is a critical component of the high-speed train. It collects power through contact with catenary, which significantly affects the running safety of the train. Pantograph with double collector strips is one common type. The aerodynamic performance of the collector strips may affect the current collection of the pantograph. In this study, the aerodynamic performance of the pantograph with double strips is investigated. The numerical results are consistent with the experimental ones. The error in the aerodynamic drag force of the pantograph between numerical and experimental results is less than 5%. Three different conditions of the strips are studied, including… More >

Daobing Wang^{1, *}, Sergio Zlotnik^{2, *}, Pedro Díez², Hongkui Ge³, Fujian Zhou³, Bo Yu⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.2, pp. 703-720, 2020, DOI:10.32604/cmes.2020.08033

Abstract The hydraulic fracturing is a nonlinear, fluid-solid coupling and transient problem, in most cases it is always time-consuming to simulate this process numerically. In recent years, although many numerical methods were proposed to settle this problem, most of them still require a large amount of computer resources. Thus it is a high demand to develop more effificient numerical approaches to achieve the real-time monitoring of the fracture geometry during the hydraulic fracturing treatment. In this study, a reduced order modeling technique namely Proper Generalized Decomposition (PGD), is applied to accelerate the simulations of the transient, non-linear coupled system of hydraulic… More >

Mahdi Soltanmohammadi¹, Vahid Monfared^2,*

Sound & Vibration, Vol.53, No.5, pp. 177-198, 2019, DOI:10.32604/sv.2019.05811

Abstract Dry-Type Cast Resin Distribution Transformers (CRT) is the secondgeneration of air-cooled distribution transformers where oil is replaced by resin for electrical insulation. CRT transformers may installed indoor adjacent to or near residential areas since they are clean and safe comparing to the conventional transformers. But, as it is obvious, noise discrepancy is intrinsically accompanied with all types of transformers and is inevitable for CRT transformers too. Minimization of noise level caused by such these transformers has biological and ergonomic importance. As it is known the core of transformers is the main source of the noise generation. In this paper, experimental… More >

S. Baragetti¹, F. Tordini²

Structural Durability & Health Monitoring, Vol.3, No.3, pp. 165-176, 2007, DOI:10.3970/sdhm.2007.003.165

Abstract The effect of a TiN PVD (Physical Vapor Deposition) coating on the fatigue behaviour of the titanium alloy Ti-6Al-4V was investigated. Fatigue tests were performed on coated and uncoated, both smooth and 120° V-notched, specimens in order to evaluate the influence of the coating on the substrate fatigue resistance. Numerical analyses were carried out in order to determine the stress distributions below the specimen surface and on the coating. Several coating elastic moduli were used in such calculations. The residual stress gradient induced by the coating process deposition and the substrate plasticization were also taken into account with FEM. The… More >

Dingqian Ding^1,2, Yongtu Liang^1,*, Yansong Li^1,3, Jianfei Sun¹, Dong Han¹, Jing Liu⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.1, pp. 273-290, 2019, DOI:10.32604/cmes.2019.07228

Abstract The solid particle impurities generated by pipe wall corrosion might deposit at the elbow of hilly pipelines during the production shutdown of oil pipelines. These solid particle impurities will seriously affect the safety of the pipeline operation and the quality of the petroleum products. Thus, it is necessary to study the methods of removing these trapped particles from pipelines. At present, the most common way to remove these solid particle impurities is pigging oil pipelines periodically by utilizing the mechanical pigging method, while the frequent pigging operation will increase the cost and risk of pipeline operation. It is very convenient… More >

Mehdi Sarmast^1,*, Hamed Ghafari², Jan R. Wright³

Sound & Vibration, Vol.53, No.3, pp. 75-95, 2019, DOI:10.32604/sv.2019.04193

Abstract One of the practical approaches in identifying structures is the non-linear resonant decay method which identifies a non-linear dynamic system utilizing a model based on linear modal space containing the underlying linear system and a small number of extra terms that exhibit the non-linear effects. In this paper, the method is illustrated in a simulated system and an experimental structure. The main objective of the non-linear resonant decay method is to identify the non-linear dynamic systems based on the use of a multi-shaker excitation using appropriated excitation which is obtained from the force appropriation approach. The experimental application of the… More >