Souli Mhamed¹, Paul Du Bois², Essam Al-Bahkali^3,*

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.1, pp. 91-107, 2018, DOI:10.31614/cmes.2018.03888

Abstract When the simulation takes account of dissipative mechanisms, e.g. heat conduction and viscosity, the shocks become smeared out to produce thin layers of rapidly and continuously varying energy, density, pressure and velocity rather than discrete surfaces of mathematical discontinuity. In the mid twentieth century, Von Neumann and Richtmyer suggested the use of a viscous pressure term (bulk viscosity) in the equilibrium equations for ideal gases in order to examine the shock while avoiding numerical oscillations at the shock front. When the bulk viscosity is included in the conservation equations, the comprehensive physics present a continuous solution satisfying the Rankine-Hugoniot conditions.… More >

Long Jiao^1,2, Zhibin Wang^1,2, Rong Chen^1,2,*, Xun Zhu^1,2, Qiang Liao^1,2, Dingding Ye^1,2, Biao Zhang^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.3, pp. 144-146, 2019, DOI:10.32604/icces.2019.04734

Abstract With the advances in micro total analysis systems (µTAS), the droplet-based microfluidics, which manipulates mini discrete droplets in an immiscible continuous phase to accomplish various detections, has been applied to many fields including medicine, pharmacy, fine-chemistry and biotechnology as it offers distinct advantages, such as small diffusion length, high-throughput, precise control and integratability [1]. As compared to the continuous-flow microfluidics, the samples in the droplet-based microfluidics are isolated by a defined droplet/continuous phase interface, avoiding the cross contamination and resulting in a controllable reaction environment. In the droplet-based microfluidics, the control of the droplet temperature with prominent temporal spatial resolution… More >

Seon Doo Jo¹, Chan Kyu Park², Jae Hong Jeong², Seung Hoon Lee², Seung Hee Kwon³

CMC-Computers, Materials & Continua, Vol.27, No.3, pp. 189-210, 2012, DOI:10.3970/cmc.2011.027.189

Abstract When concrete is being pumped, a lubricating layer forms at the interface of the inner concrete and the wall of the pipe. The lubricating layer is one of the most dominant factors in determining the pumping capability, yet no study has endeavored to quantitatively estimate the thickness and rheological properties of the layer. Recently, there has been a growing demand for large-scale construction under extreme conditions, such as high-rise buildings and super-long span bridges. This demand has heightened the need for more accurate predictions of pumpability.
A possible mechanism that contributes to the formation of the lubricating layer is shear-induced… More >

Chung-Fu Chen¹, Yi-Chia Cheng¹, Che-Wun Hong^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.3, pp. 263-283, 2015, DOI:10.3970/cmes.2015.109.263

Abstract Based on the Hellmann-Feynman theorem, which integrates the molecular dynamics simulation with computational quantum mechanics, this research simulates the ionic transport in the LiCl-KCl molten salt materials using so called “first principles molecular dynamics (FPMD)” technique without employing an empirical potential model. The main purpose of this computational FPMD focuses on the evaluation of important transport properties, such as diffusion coefficient, ionic conductivity, shear viscosity, and thermal conductivity, using the Green-Kubo relationship. All simulation results agree well with experimental data published in existing literatures within an acceptable range. FPMD calculations are proved to be a powerful tool for prediction of… More >

Jason F. Hammond¹, Elizabeth J. Stewart², John G. Younger³, Michael J.Solomon², David M. Bortz^4,5

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.3, pp. 295-340, 2014, DOI:10.32604/cmes.2014.098.295

Abstract The overall goal of this work is to develop a numerical simulation which correctly describes a bacterial biofilm fluid-structure interaction and separation process. In this, the first of a two-part effort, we fully develop a convergent scheme and provide numerical evidence for the method order as well as a full 3D separation simulation. We use an immersed boundary-based method (IBM) to model and simulate a biofilm with density and viscosity values different from than that of the surrounding fluid. The simulation also includes breakable springs connecting the bacteria in the biofilm which allows the inclusion of erosion and detachment into… More >

G. Narbona-Reina¹, J.D.D. Zabsonré², E.D. Fernández-Nieto¹, D. Bresch³

CMES-Computer Modeling in Engineering & Sciences, Vol.43, No.1, pp. 27-72, 2009, DOI:10.3970/cmes.2009.043.027

Abstract In this work we present a new two-dimensional bilayer Shallow-Water model including viscosity and friction effects on the bottom and interface level. It is obtained following [Gerbeau and Perthame (2001)] from an asymptotic analysis of non-dimensional and incompressible Navier-Stokes equations with hydrostatic approximation. In order to obtain the viscosity effects into the model we must have into account a second order approximation. To evaluate this model we perform two numerical tests consisting of an internal dam-break problem for both, one and two dimensional cases. In the first one we make a comparison between the model obtained and the Navier-Stokes simulation. More >

Wenzhong Tang¹, Suresh G. Advani¹

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.2, pp. 165-176, 2005, DOI:10.3970/cmes.2005.008.165

Abstract An optimization method is proposed to simulate the motion of long flexible fibers in shear flow. The fiber is modeled as spheres connected by massless rigid rods and ball-socket joints. The optimization method is mathematically justified and used to obtain the position of a fiber at the next time step from its current position. Results for a single fiber in simple shear flow agree well with those reported in the literature. The usefulness of the method is demonstrated by simulating the motion of two interactive fibers subjected to shear flow field, and by studying the viscosity of dilute suspensions of… More >

Qiuren Ou^1,2,*, Peijun Ji², Jun Xiao¹, Ling Wu²

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.1, pp. 27-37, 2019, DOI:10.32604/fdmp.2019.04787

Abstract The properties of resin transfer molding (RTM) cyanate ester and its T800 grade carbon fiber composites were studied with the rheometer, differential scanning calorimetry (DSC), FT-IR, dynamic mechanical analyzer (DMA), thermal gravimetric analysis (TGA), mechanical property testing, and scanning electron microscopy (SEM). The results showed that the temperature of cyanate ester suitable for RTM process was 70℃. Curing process of the resin was 130℃/2 h+160℃/2 h+200℃/2 h+220℃/4 h. Glass transition temperature and heat decomposition temperature of the cured resin are 289℃ and 415℃, respectively. Mechanical properties of T800/RTM cyanate composites are 13.5% higher than that of T700/RTM cyanate composites and… More >

Anupam Bh,ari¹, Vipin Kumar²

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.3, pp. 359-375, 2014, DOI:10.3970/fdmp.2014.010.359

Abstract The purpose of this paper is to study the flow characteristics of a ferrofluid revolving through a porous medium with a magnetic-field-dependent viscosity in the presence of a stationary disk. A Finite Difference Method is employed to discretize the set of nonlinear coupled differential equations involved in the problem. The discretized nonlinear equations, in turn, are solved by a Newton method (using MATLAB) taking the initial guess with the help of a PDE Solver. Results displayed in graphical form are used to assess the effect of the variable viscosity and porosity parameters on the velocity components. The displacement thickness of… More >

Paras Ram^1,2, Vikas Kumar³

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.2, pp. 179-196, 2014, DOI:10.3970/fdmp.2014.010.179

Abstract The present study is carried out to examine the effects of temperature dependent variable viscosity on the three dimensional steady axi-symmetric Ferrohydrodynamic (FHD) boundary layer flow of an incompressible electrically nonconducting magnetic fluid in the presence of a rotating disk. The disk is subjected to an externally applied magnetic field and is maintained at a uniform temperature. The nonlinear coupled partial differential equations governing the boundary layer flow are non dimensionalized using similarity transformations and are reduced to a system of coupled ordinary differential equations. To study the effects of temperature dependent viscosity on velocity profiles and temperature distribution within… More >