Open Access
ARTICLE
Primož Kocutar1, *, Jure Ravnik1, Leopold Škerget1
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 1-22, 2020, DOI:10.32604/cmes.2020.08728
Abstract In this paper, we develop and test a unified hybrid LES/URANS turbulence
model with two different Large Eddy Simulation (LES) turbulence models. The numerical
algorithm is based on the Boundary Element Method. In the existing hybrid LES/URANS
turbulence model we implemented a new Smagorinsky LES turbulence model. The
hybrid LES/URANS turbulence model is unified, which means that the LES/URANS
interface is changed dynamically during simulation using a physical quantity. In order
to define the interface between LES and unsteady Reynolds Averaged Navier Stokes
(URANS) zones during the simulation, we use the Reynolds number based on turbulent
kinetic energy as a… More >
Open Access
ARTICLE
Davide Piovesan1, *, Roberto Bortoletto2
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 23-47, 2020, DOI:10.32604/cmes.2020.09231
（This article belongs to this Special Issue: Computer Methods in Bio-mechanics and Biomedical Engineering)
Abstract Exoskeletons are designed to control the forces exerted during the physical
coupling between the human and the machine. Since the human is an active system, the
control of an exoskeleton requires coordinated action between the machine and the load
so to obtain a reciprocal adaptation. Humans in the control loop can be modeled as active
mechanical loads whose stiffness is continuously changing. The direct measurement of
human stiffness is difficult to obtain in real-time, thus posing a significant limitation to
the design of wearable robotics controllers. Electromyographic (EMG) recordings can
provide an indirect estimation of human muscle force and stiffness,… More >
Open Access
ARTICLE
Jianhua Dong1, Lifeng Wu2, Xiaogang Liu1, *, Cheng Fan1, Menghui Leng3, Qiliang Yang1
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 49-73, 2020, DOI: 10.32604/cmes.2020.09014
Abstract Solar radiation is an important parameter in the fields of computer modeling,
engineering technology and energy development. This paper evaluated the ability of three
machine learning models, i.e., Extreme Gradient Boosting (XGBoost), Support Vector
Machine (SVM) and Multivariate Adaptive Regression Splines (MARS), to estimate the
daily diffuse solar radiation (Rd). The regular meteorological data of 1966-2015 at five
stations in China were taken as the input parameters (including mean average temperature
(Ta), theoretical sunshine duration (N), actual sunshine duration (n), daily average air
relative humidity (RH), and extra-terrestrial solar radiation (Ra)). And their estimation
accuracies were subjected to comparative analysis.… More >
Open Access
ARTICLE
Min Luo1, Tingting Xu1, *, Jiajun Jiang2, Xu Chi3, Jing Wang4, Shihua Xue1
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 75-100, 2020, DOI:10.32604/cmes.2020.09236
Abstract The lack of research on flexible drilling tool leads to limited application of
ultra-short radius horizontal wells. The flexible drilling tool is different from the
conventional drilling tool. The flexible drilling pipe involves a mutual transition between
the structure and the mechanism during the deformation process. At the same time, the
flexible drilling pipe and the eccentric guide tube, the guide tube and the wellbore
generate random contact. In this paper, 3-D beam elements, universal joint elements,
rigid beam elements and the beam-beam contact elements are combined to establish a
two-layer contact nonlinear finite element model of the flexible drilling… More >
Open Access
ARTICLE
Meijuan Shan1, 2, Libin Zhao2, *, Wei Huang3, Fengrui Liu2, Jianyu Zhang4, *
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 101-127, 2020, DOI:10.32604/cmes.2020.09099
Abstract The high demands for load-carrying capability and structural efficiency of
composite-metal bolted joints trigger in-depth investigations on failure mechanisms of the
joints in hygrothermal environments. However, few studies have been presented to exhaustively reveal hygrothermal effects on the failure of CFRP-metal bolted joints, which
differ from CFRP-CFRP or metal-metal bolted joints because of the remarkably different
material properties of CFRPs and metals. In this paper, hygrothermal effects on tensile failures
of single-lap and double-lap CFRP-aluminum bolted joints were experimentally and
numerically investigated. A novel numerical model, in which a hygrothermal-included
progressive damage model of composites was established and elastic-plastic models… More >
Open Access
ARTICLE
Xu Liu1, Xiaoyang Chen1, *, Rongyu Kang1, Xuejin Shen1, Ben Ni2
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 129-152, 2020, DOI:10.32604/cmes.2020.07836
Abstract In this paper, the oscillatory oil squeeze film is taken as a research object, and
a coupled cavitation model based on the theory of bubble dynamics and hydrodynamic
lubrication is used and a specific method of numerical calculation is given. Then the
parallel-plate squeeze film test apparatus is used to validate the coupled cavitation model.
The pictures of the cavitation were captured by a high-speed camera and then processed
to obtain the variation of the cavitation area in experiments. Compared with the
experimental results, the model can successfully predict the process of generation and
development of cavitation. At the same… More >
Open Access
ARTICLE
Xiang Liu1, Liangbo Sun2, Mingzhen Wang3, 4, Bin Li2, Lisheng Liu1, 5, *
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 153-183, 2020, DOI:10.32604/cmes.2020.08716
Abstract A vein model was established to simulate the periodic characteristics of blood
flow and valve deformation in blood-induced valve cycles. Using an immersed finite
element method which was modified by a ghost fluid technique, the interaction between
the vein and blood was simulated. With an independent solid solver, the contact force
between vein tissues was calculated using an adhesive contact method. A benchmark
simulation of the normal valve cycle validated the proposed model for a healthy vein.
Both the opening orifice and blood flow rate agreed with those in the physiology. Low
blood shear stress and maximum leaflet stress were… More >
Open Access
ARTICLE
Yongping Yu1, Lihui Chen1, Shaopeng Zheng1, Baihui Zeng1, Weipeng Sun2, ∗
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 185-200, 2020, DOI:10.32604/cmes.2020.07997
Abstract This paper is focused on the post-buckling behavior of the fixed laminated
composite beams with effects of axial compression force and the shear deformation. The
analytical solutions are established for the original control equations (that is not
simplified) by applying the Maclaurin series expansion, Chebyshev polynomials, the
harmonic balance method and the Newton’s method. The validity of the present method
is verified via comparing the analytical approximate solutions with the numerical ones
which are obtained by the shooting method. The present third analytical approximate
solutions can give excellent agreement with the numerical solutions for a wide range of
the deformation… More >
Open Access
ARTICLE
Yao Ma1, Xibiao Cai1, *, Fuming Sun2
CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 201-216, 2020, DOI:10.32604/cmes.2020.07867
（This article belongs to this Special Issue: Security Enhancement of Image Recognition System in IoT based Smart Cities)
Abstract Image quality assessment has become increasingly important in image quality
monitoring and reliability assuring of image processing systems. Most of the existing
no-reference image quality assessment methods mainly exploit the global information of
image while ignoring vital local information. Actually, the introduced distortion depends
on a slight difference in details between the distorted image and the non-distorted reference
image. In light of this, we propose a no-reference image quality assessment method based
on a multi-scale convolutional neural network, which integrates both global information
and local information of an image. We first adopt the image pyramid method to generate
four scale… More >
Open Access
ARTICLE
Shuifen Zhan1, 2, 3, Mingchao Wang2, *, Min Wang5, *, 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
（This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
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 >
Login
Register
Submit a Paper
Propose a Special lssue