S. Chen^1,2, Y. Liu^1,3, B.C. Khoo⁴, X.J. Fan⁵, J.T. Fan⁶

CMES-Computer Modeling in Engineering & Sciences, Vol.19, No.3, pp. 181-196, 2007, DOI:10.3970/cmes.2007.019.181

Abstract The mesoscopic simulation for fluids flow in a square microchannel is investigated using dissipative particle dynamics. The velocity distribution for single fluid in a square channel is compared with the solutions of CFD solver, which is found to be in good agreement with each other. The no-slip boundary condition could be well held for the repulsive coefficient ranged from 9.68 to 18.0. For the same range of repulsive coefficient, various wettabilities could be obtained by changing the repulsive coefficient for binary immiscible fluids, in which the immiscible fluids are achieved by increasing the repulsive force… More >

Heng Xie¹, Seiichi Koshizuka², Yoshiaki Oka²

CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.1, pp. 1-16, 2007, DOI:10.3970/cmes.2007.018.001

Abstract A model of a single liquid drop colliding on solid surface is developed based with Moving Particle Semi-implicit (MPS) method. The mathematical model involves gravity, viscosity and surface tension. The wettability between the impact liquid and the solid surface is modeled by the contact angle model and the non-slip boundary condition. The particles of the drop are divided into four types in which the model varies to simulate the liquid particles in different area. The model is validated by the comparison of the theoretical results. The complete dynamic process including the spreading, the recoiling, re-bouncing More >

Zhentao Wang^1,*, Kai Dong, Shuiqing Zhan

FDMP-Fluid Dynamics & Materials Processing, Vol.13, No.4, pp. 221-234, 2017, DOI:10.3970/fdmp.2017.013.221

Abstract We have investigated the unsteady internal flow occurring in an evaporating droplet interacting with a high-temperature atmospheric environment. The Navier-Stokes equations for both the liquid and the gas phases have been solved numerically in the framework of a Volume of Fluid (VOF) method relying on the so-called Continuum Surface Force (CSF) model. A specific kernel able to account for evaporation and related phase change has been incorporated directly in the VOF approach. The temperature distributions within the droplet has been found to be relatively uniform by virtue of the Marangoni flow. The transient evolution of More >

Asghar Esmaeeli¹, Ali Behjatian¹

FDMP-Fluid Dynamics & Materials Processing, Vol.13, No.3, pp. 143-153, 2017, DOI:10.3970/fdmp.2017.013.143

Abstract The evolution of the flow field in and around a liquid drop in a unifor-m electric field for fluid systems corresponding to region (II) of the circulation-deformation map is fundamentally different than that for the rest of the map and has not been explored before. This is examined here and justified mathematical-ly. Furthermore a methodology is developed to predict the flow pattern, which is likely to be helpful in predicting the evolution of the flow field in more complex circumstances. More >

Chekifi. T^1,2, Dennai. B¹, Khelfaoui. R¹

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 205-220, 2015, DOI:10.3970/fdmp.2015.011.205

Abstract Droplet generation, splitting and sorting are investigated numerically in the framework of a VOF technique for interface tracking and a finite-volume numerical method using the commercial code FLUENT. Droplets of water-in-oil are produced by a flow focusing technique relying on the use of a microchannell equipped with an obstacle to split the droplets. The influence of several parameters potentially affecting this process is investigated parametrically towards the end of identifying "optimal" conditions for droplet breakup. Such parameters include surface tension, the capillary number and the main channel width. We show that the capillary number plays More >

Yan Shen¹, Hong Zhang^1,2,3, Hui Xu¹, Tong Bai¹, Ping Yu¹

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.1, pp. 63-81, 2014, DOI:10.3970/fdmp.2014.010.063

Abstract Single-unit and multi-unit models of porous media (metal felts) have been used to investigate thermal fluid-structure interaction phenomena in a liquid sodium system. Micro-scale aspects have been studied via numerical simulations. The permeability of metal felts has been measured experimentally to verify the reliability of the models used. This integrated approach has allowed a proper evaluation of the interdependencies among phenomena on different scales (including relevant information on skeleton deformation and pressure drop as a function of different parameters). Pressure drop generally increases with velocity and heat flux for both laminar and turbulent flows. The More >

M. Do-Quang¹, A. Carlson¹, G. Amberg¹

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.4, pp. 389-402, 2011, DOI:10.3970/fdmp.2011.007.389

Abstract Inkjet technology has been recognized as one of the most successful and promising micro-system technologies. The wide application areas of printer heads and the increasing demand of high quality prints are making ink consumption and print see-through important topics in the inkjet technology. In the present study we investigate numerically the impact of ink droplets onto a porous material that mimics the paper structure. The mathematical framework is based on a free energy formulation, coupling the Cahn-Hilliard and Navier Stokes equations, for the modelling of the two-phase flow. The case studied here consists of a More >

T. Sanada¹, K. Ando², T. Colonius²

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.4, pp. 329-340, 2011, DOI:10.3970/fdmp.2011.007.329

Abstract When a droplet impacts a solid surface at high speed, the contact periphery expands very quickly and liquid compressibility plays an important role in the initial dynamics and the formation of lateral jets. The high speed impact results in high pressures that can account for the surface erosion. In this study, we numerically investigated a high speed droplet impacts on a solid wall. The multicomponent Euler equations with the stiffened equation of state are computed using a FV-WENO scheme with an HLLC Riemann solver that accurately captures shocks and interfaces. In order to compare the More >

Malcolm R. Davidson¹, Dalton J.E. Harvie¹

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.3, pp. 317-328, 2011, DOI:10.3970/fdmp.2011.007.317

Abstract A volume-of-fluid numerical method, adapted by the authors [Harvie, Cooper-White and Davidson (2008)] to simulate the flow of viscoelastic fluids, is used to predict deformation of a viscoelastic droplet carried by an immiscible Newtonian liquid through an axisymmetric microfluidic contraction-expansion. Values of the capillary number and elasticity number are chosen based on corresponding values for a rectangular contraction for which a reentrant cavity at the rear of the drop and subsequent encapsulation behaviour was observed experimentally by Harvie, Cooper-White and Davidson (2008). A reentrant cavity, similar to the observed one, is predicted; however, encapsulation is More >

Carole Planchette¹, Elise Lorenceau¹, Günter Brenn²

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.3, pp. 279-302, 2011, DOI:10.3970/fdmp.2011.007.279

Abstract This work is dedicated to a general description of collisions between two drops of immiscible liquids. Our approach is mainly experimental and allows us to describe the outcomes of such collisions according to a set of relevant parameters. Varying the relative velocity U as well as the impact parameter X we can build for each pair of investigated liquids a nomogram X,U showing three possible regimes: coalescence, head-on separation and off-center separation. In this paper, we also study the influence of the liquid properties, i.e. viscosity, density, surface and interfacial tensions using a set of… More >