Ratha Yeu¹, Namhui Ra², Seong-A Lee³, Yunyoung Nam^4,*

CMC-Computers, Materials & Continua, Vol.66, No.2, pp. 1411-1425, 2021, DOI:10.32604/cmc.2020.013761

Abstract Electrocardiogram (ECG) electrodes are conductive pads applied to the skin to measure cardiac activity. Ag/AgCl electrodes are the commercial product which widely used to obtain ECGs. When monitoring the ECG in a hot spring, Ag/AgCl electrodes must be waterproofed; however, this is time-consuming, and the adhesive may tear the skin on removal. For solving the problem, we developed the carbon pencil lead (CPL) electrodes for use in hot springs. Both CPL and Ag/AgCl electrodes were connected to ECG100C’s cables. The Performance was evaluated in three conditions as following: hot spring water with and without bubble, and in cold water. In… More >

Xu Liu¹, Xiaoyang Chen^{1, *}, 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 >

Soon Wan Chung¹, Yoo Jin Choi¹, Seung Jo Kim¹

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.6, pp. 707-718, 2003, DOI:10.3970/cmes.2003.004.707

Abstract In this paper, an automatic finite element remeshing algorithm based on the bubble packing method is utilized for the purpose of numerical simulations of localized damage, because fine meshes are needed to represent the gradually concentrated damage. The bubble packing method introduces two parameters that easily control the remeshing criterion and the new mesh size. The refined area is determined by \textit {a posteriori} error estimation utilizing the value obtained from Superconvergent Patch Recovery. The isotropic ductile damage theory, founded on continuum damage mechanics, is used for this damage analysis. It was successfully shown in the numerical examples (upsetting and… More >

Yang Li¹, Wenjing Zhou^1,*, Yonghai Zhang¹, Baojin Qi¹, Jinjia Wei^{1, 2, *}

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.3, pp. 151-151, 2019, DOI:10.32604/icces.2019.04982

Abstract Nucleation boiling is used in a wide range of engineering and science fields, such as electronics cooling, new energy and the microelectromechanical systems (MEMS) technology. Besides, a better understanding of the nucleation is fundmental significance for the application and enchcement of nucleation boiling in the traditional and modern high-tech industries. Unfortunately, due to the complexity of physical mechanisms in nanoscale and the limit of small scale, accurate experimentation of nucleation cannot be accomplished. Therefore, it is important to study the influence of solid properties on nucleation despite its general importance by performing molecular dynamics simulation researches. In present work, we… More >

Prabhakar Misra¹, Silvina M. Gatica¹, Obafemi Otelaja²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.4, pp. 205-210, 2008, DOI:10.3970/icces.2008.005.205

Abstract Nanobubbles form either spontaneously or by induction at the surface of certain solids immersed in a liquid. Atomic Force Microscopy observations have confirmed their formation. Such bubbles have sizes in the range 10-100 nm and have important ramifications for properties of interfaces and could be responsible for long-range hydrophobic attractive forces. In addition, as a potential application, the use of nanobubbles -- in tandem with ultrasound -- has been proposed for the treatment of strokes. Formation of nanobubbles at the water-graphite interface influences the adsorption of nanoparticles and the corresponding wetting properties. An important parameter relevant to the stability of… More >

Zhaoli Tian^1,2, Yunlong Liu^1,2,*, Shiping Wang¹, A Man Zhang¹, Youwei Kang³

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 397-423, 2019, DOI:10.31614/cmes.2019.04419

Abstract The low frequency load of an underwater explosion bubble and the generated waves can cause significant rigid motion of a ship that threaten its stability. In order to study the fluid-structure interaction qualitatively, a two-dimensional underwater explosion bubble dynamics model, based on the potential flow theory, is established with a double-vortex model for the doubly connected bubble dynamics simulation, and the bubble shows similar dynamics to that in 3-dimensional domain. A fully nonlinear fluid-structure interaction model is established considering the rigid motion of the floating body using the mode-decomposition method. Convergence test of the model is implemented by simulating the… More >

Zhijie Huang^1,2,3, Zuyu Chen^1,2,3, Xiaodan Ren^4,*, Jing Hu³, Xuedong Zhang³, Lu Hai⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.1, pp. 139-155, 2019, DOI:10.31614/cmes.2019.04596

Abstract Damage and threats to hydraulic and submarine structures by underwater explosions (UNDEXs) have raised much attention. The centrifuge model test, compared to prototype test, is a more promising way to examine the problem while reducing cost and satisfying the similitude requirements of both Mach and Froude numbers simultaneously. This study used a systematic approach employing centrifuge model tests and numerical simulations to investigate the effects of UNDEXs on an air-backed steel plate. Nineteen methodical centrifuge tests of UNDEXs were conducted. The shock wave pressure, bubble oscillation pressure, acceleration and the strain of the air-backed steel plate were recorded and compared… More >

F.Z. Chen^1,2, H.F. Qiang¹, W.R. Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.1, pp. 41-68, 2015, DOI:10.3970/cmes.2015.104.041

Abstract A coupled method describing gas-solid two-phase flow has been proposed to numerically study the bubble formation at a single orifice in gas-fluidized beds. Solid particles are traced with smoothed particle hydrodynamics, whereas gas phase is discretized by finite volume method. Drag force, gas pressure gradient, and volume fraction are used to couple the two methods. The effect of injection velocities, particle sizes, and particle densities on bubble growth is analyzed using the coupled method. The simulation results, obtained for two-dimensional geometries, include the shape and diameter size of a bubble as a function of time; such results are compared with… More >

Tai C. Lee¹, Huan J. Keh²

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.5, pp. 317-333, 2013, DOI:10.3970/cmes.2013.093.317

Abstract A theoretical study of the thermocapillary migration of a fluid sphere located at an arbitrary position inside a spherical cavity is presented in the quasisteady limit of small Reynolds and Marangoni numbers. The applied temperature gradient is perpendicular to the line through the drop and cavity centers. The general solutions to the energy and momentum equations governing the system are constructed from the superposition of their fundamental solutions in the spherical coordinates originating from the two centers, and the boundary conditions are satisfied by a multipole collocation method. Results for the thermocapillary migration velocity of the drop are obtained for… More >

W.W. Zhang¹, Y.F. Nie¹, Y.Q. Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.6, pp. 507-530, 2012, DOI:10.3970/cmes.2012.088.507

Abstract A new algorithm for anisotropic triangular meshes generation in two dimension is presented. The inputs to the algorithm are the boundary geometry information and a metric tensor that specifies the desired element size and shape. The initial nodes are firstly distributed according to the above mentioned geometrical information, after bubble simulation, the optimized nodes set that meets the requirements of the metric tensor is obtained quickly. Then taking full advantage of the nodes set and the adjacency lists information provided by the process of node placement, a handful of non-satellite nodes are removed from the adjacency lists of the nodes… More >