Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method

While various phase-field models have recently appeared for two-phase fluids with different densities, only some are known to be thermodynamically consistent, and practical stable schemes for their numerical simulation are lacking. In this paper, we derive a new form of thermodynamically-consistent...

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Main Authors: Roudbari, M. Shokrpour, Şimşek, G., Brummelen, E.H. van, van der Zee, Kristoffer George
Format: Article
Published: World Scientific Publishing 2018
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Online Access:https://eprints.nottingham.ac.uk/48655/
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author Roudbari, M. Shokrpour
Şimşek, G.
Brummelen, E.H. van
van der Zee, Kristoffer George
author_facet Roudbari, M. Shokrpour
Şimşek, G.
Brummelen, E.H. van
van der Zee, Kristoffer George
author_sort Roudbari, M. Shokrpour
building Nottingham Research Data Repository
collection Online Access
description While various phase-field models have recently appeared for two-phase fluids with different densities, only some are known to be thermodynamically consistent, and practical stable schemes for their numerical simulation are lacking. In this paper, we derive a new form of thermodynamically-consistent quasi-incompressible diffuse-interface Navier–Stokes–Cahn–Hilliard model for a two-phase flow of incompressible fluids with different densities. The derivation is based on mixture theory by invoking the second law of thermodynamics and Coleman–Noll procedure. We also demonstrate that our model and some of the existing models are equivalent and we provide a unification between them. In addition, we develop a linear and energy-stable time-integration scheme for the derived model. Such a linearly-implicit scheme is nontrivial, because it has to suitably deal with all nonlinear terms, in particular those involving the density. Our proposed scheme is the first linear method for quasi-incompressible two-phase flows with non-solenoidal velocity that satisfies discrete energy dissipation independent of the time-step size, provided that the mixture density remains positive. The scheme also preserves mass. Numerical experiments verify the suitability of the scheme for two-phase flow applications with high density ratios using large time steps by considering the coalescence and breakup dynamics of droplets including pinching due to gravity.
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spelling nottingham-486552020-05-04T19:34:47Z https://eprints.nottingham.ac.uk/48655/ Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method Roudbari, M. Shokrpour Şimşek, G. Brummelen, E.H. van van der Zee, Kristoffer George While various phase-field models have recently appeared for two-phase fluids with different densities, only some are known to be thermodynamically consistent, and practical stable schemes for their numerical simulation are lacking. In this paper, we derive a new form of thermodynamically-consistent quasi-incompressible diffuse-interface Navier–Stokes–Cahn–Hilliard model for a two-phase flow of incompressible fluids with different densities. The derivation is based on mixture theory by invoking the second law of thermodynamics and Coleman–Noll procedure. We also demonstrate that our model and some of the existing models are equivalent and we provide a unification between them. In addition, we develop a linear and energy-stable time-integration scheme for the derived model. Such a linearly-implicit scheme is nontrivial, because it has to suitably deal with all nonlinear terms, in particular those involving the density. Our proposed scheme is the first linear method for quasi-incompressible two-phase flows with non-solenoidal velocity that satisfies discrete energy dissipation independent of the time-step size, provided that the mixture density remains positive. The scheme also preserves mass. Numerical experiments verify the suitability of the scheme for two-phase flow applications with high density ratios using large time steps by considering the coalescence and breakup dynamics of droplets including pinching due to gravity. World Scientific Publishing 2018-04-30 Article PeerReviewed Roudbari, M. Shokrpour, Şimşek, G., Brummelen, E.H. van and van der Zee, Kristoffer George (2018) Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method. Mathematical Models and Methods in Applied Sciences, 28 (4). ISSN 1793-6314 Navier-Stokes Cahn-Hilliard; Quasi-incompressible two-phase-flow; Mixture theory; Thermodynamic consistency; Diffuse interface; Energy-stable scheme https://www.worldscientific.com/doi/abs/10.1142/S0218202518500197 doi:10.1142/S0218202518500197 doi:10.1142/S0218202518500197
spellingShingle Navier-Stokes Cahn-Hilliard; Quasi-incompressible two-phase-flow; Mixture theory; Thermodynamic consistency; Diffuse interface; Energy-stable scheme
Roudbari, M. Shokrpour
Şimşek, G.
Brummelen, E.H. van
van der Zee, Kristoffer George
Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method
title Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method
title_full Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method
title_fullStr Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method
title_full_unstemmed Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method
title_short Diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method
title_sort diffuse-interface two-phase flow models with different densities: a new quasi-incompressible form and a linear energy-stable method
topic Navier-Stokes Cahn-Hilliard; Quasi-incompressible two-phase-flow; Mixture theory; Thermodynamic consistency; Diffuse interface; Energy-stable scheme
url https://eprints.nottingham.ac.uk/48655/
https://eprints.nottingham.ac.uk/48655/
https://eprints.nottingham.ac.uk/48655/