Abstract
The flow of two-dimensional drops on an inclined channel is studied by numerical simulations at finite Reynolds numbers. The effect of viscosity ratio on the behaviour of the two-phase medium is examined. The flow is driven by the acceleration due to gravity, and there is no pressure gradient along the flow direction. An implicit version of the finite difference/front-tracking method was developed and used in the present study. The lateral migration of a drop is studied first. It is found that the equilibrium position of a drop moves away from the channel floor as the viscosity ratio increases. However, the trend reverses beyond a certain viscosity ratio. Simulations with 40 drops in a relatively large channel show that there exists a limiting viscosity ratio where the drops behave like solid particles, and the effect of internal circulation of drops becomes negligible. This limiting condition resembles the granular flow regime except that the effect of interstitial fluid is present. The limiting viscosity ratio depends on the flow conditions (80 for \(Re=10\), and 200 for \(Re=20\)). There are two peaks in the areal fraction distribution of drops across the channel which is different from granular flow regime. It is also found that the peak in areal fraction distribution of drops moves away from the channel floor as the inclination angle of the channel increases.
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References
Adams, J.: Multigrid Fortran software for the efficient solution of linear elliptic partial differential equations. Appl. Math. Comput. 34, 113–146 (1989)
Bayareh, M., Mortazavi, S.: Three-dimensional numerical simulation of drops suspended in simple shear flow at finite Reynolds numbers. Int. J. Multiph. Flow 37, 1315–1330 (2011)
Campbell, C.S., Brennen, C.E.: Chute flows of granular material: some computer simulations. J. Appl. Mech. 52, 172–178 (1985)
Coulliette, C., Pozrikidis, C.: Motion of an array of drops through a cylindrical tube. J. Fluid Mech. 358, 1–28 (1998)
Feng, J., Hu, H.H., Joseph, D.D.: Direct simulation of initial value problems for the motion of solid bodies in a Newtonian fluid. Part 2. Couette and Poiseuille flows. J. Fluid Mech. 261, 271–301 (1994)
Goldsmith, H.L., Mason, S.G.: The flow of suspensions through tubes. I. Single spheres, rods, and discs. J. Colloid Sci. 17, 448–476 (1962)
Griggs, A.J., Zinchenko, A.Z., Davis, R.H.: Gravity-driven motion of a drop or bubble near an inclined plane at low Reynolds number. Int. J. Multiph. Flow 34, 408–413 (2008)
Harlow, F.H., Eddie Welch, J.: Numerical calculation of time-dependent viscous incompressible flow of fluid with free surface. Phys. Fluids 8, 2182–2189 (1965)
Ho, B.P., Leal, L.G.: Inertial migration of rigid spheres in two-dimensional unidirectional flows. J. Fluid Mech. 65, 365–400 (1974)
Janssen, P.J.A., Anderson, P.D.: A boundary-integral model for drop deformation between two parallel plates with non-unit viscosity ratio drops. J. Comput. Phys. 227, 8807–8819 (2008)
Karnis, A., Goldsmith, H.L., Mason, S.G.: Axial migration of particles in Poiseuille flow. Nature 200, 159–160 (1963)
Karnis, A., Goldsmith, H.L., Mason, S.G.: The flow of suspensions through tubes: V. Inertial effects. Can. J. Chem. Eng. 44, 181–193 (1966)
Kowalewski, T.A.: Concentration and velocity measurements in the flow of droplet suspensions through tube. Exp. Fluids 2, 213–219 (1984)
Li, X., Pozrikidis, C.: Film flow of a suspension of liquid drops. Phys. Fluids 14, 61–74 (2002)
Mortazavi, S., Tryggvason, G.: A numerical study of the motion of drops in Poiseuille flow. Part 1. Lateral migration of one drop. J. Fluid Mech. 41, 325–350 (2000)
Mortazavi, S., Tafreshi, M.M.: On the behavior of suspension of drops on an inclined surface. Phys. A 392, 58–71 (2013)
Nourbakhsh, A., Mortazavi, S., Afshar, Y.: Three-dimensional numerical simulation of drops suspended in Poiseuille flow at non-zero Reynolds numbers. Phys. Fluids 23, 123303–123311 (2011)
Oliver, D.R., Silberberg, A.: Influence of particle rotation on radial migration in the Poiseuille flow of suspensions. Nature 194, 1269–1271 (1962)
Peyret, R., Taylor, T.D.: Computational Methods for Fluid Flow. Springer, Berlin (1983)
Segre, G., Silberberg, A.: Radial particle displacements in Poiseuille flow of suspensions. Nature 189, 209–210 (1961)
Segre, G., Silberberg, A.: Behavior of macroscopic rigid spheres in Poiseuille flow Part 1. Determination of local concentration by statistical analysis of particle passages through crossed light beams. J. Fluid Mech. 14, 115–135 (1962)
Segre, G., Silberberg, A.: Behavior of macroscopic rigid spheres in Poiseuille flow Part II. Experimental results and interpretation. J. Fluid Mech. 14, 136–157 (1962)
Unverdi, S.O., Tryggvason, G.: A front-tracking method for viscous, incompressible, multi-fluid flows. J. Comput. Phys. 100, 25–37 (1992)
Zhou, H., Pozrikidis, C.: Pressure-driven flow of suspensions of liquid drops. Phys. Fluids 6, 80–94 (1994)
Zhou, H., Pozrikidis, C.: The flow of ordered and random suspensions of two-dimensional drops in a channel. J. Fluid Mech. 255, 103–127 (1993)
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Communicated by Tim Phillips.
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Aberuee, M., Mortazavi, S. Effect of viscosity ratio on the motion of drops flowing on an inclined surface. Theor. Comput. Fluid Dyn. 32, 73–90 (2018). https://doi.org/10.1007/s00162-017-0438-9
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DOI: https://doi.org/10.1007/s00162-017-0438-9