A robust and accurate adaptive approximation method for a diffuse-interface model of binary-fluid flows

T. H.B. Demont*, G. J. van Zwieten, C. Diddens, E. H. van Brummelen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Scopus)
28 Downloads (Pure)

Abstract

We present an adaptive simulation framework for binary-fluid flows, based on the Abels–Garcke–Grün Navier–Stokes–Cahn–Hilliard (AGG NSCH) diffuse-interface model. The adaptive-refinement procedure is guided by a two-level hierarchical a-posteriori error estimate, and it effectively resolves the spatial multiscale behavior of the diffuse-interface model. To improve the robustness of the solution procedure and avoid severe time-step restrictions for small-interface thicknesses, we introduce an ɛ-continuation procedure, in which the diffuse interface thickness (ɛ) are enlarged on coarse meshes, and the mobility is scaled accordingly. To further accelerate the computations and improve robustness, we apply a modified Backward Euler scheme in the initial stages of the adaptive-refinement procedure in each time step, and a Crank–Nicolson scheme in the final stages of the refinement procedure. To enhance the robustness of the nonlinear solution procedure, we introduce a partitioned solution procedure for the linear tangent problems in Newton's method, based on a decomposition of the NSCH system into its NS and CH subsystems. We conduct a systematic investigation of the conditioning of the monolithic NSCH tangent matrix and of its NS and CH subsystems for a representative 2D model problem. To illustrate the properties of the presented adaptive simulation framework, we present numerical results for a 2D oscillating water droplet suspended in air, and we validate the obtained results versus those of a corresponding sharp-interface model.

Original languageEnglish
Article number115563
JournalComputer methods in applied mechanics and engineering
Volume400
Early online date14 Sept 2022
DOIs
Publication statusPublished - 1 Oct 2022

Keywords

  • Adaptive refinement
  • Binary-fluid flows
  • Diffuse-interface models
  • Navier–Stokes–Cahn–Hilliard equations
  • Partitioned solution methods
  • ɛ-continuation

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