Abstract

To study natural convection problems in two-phase flows, a non-isothermal two-phase flow model incorporating differential viscosities and thermal diffusivities is considered and analyzed via the phase-field method. This modeling framework involves the Multiphysics coupling of the Cahn-Hilliard phase field equations, heat transfer equation, and Navier-Stokes equations, resulting in a strongly nonlinear system. To efficiently solve the sophisticated system, we develop, analyze, and demonstrate a decoupled linear fully discrete scheme, which leverages the invariant energy quadratization strategy for the Cahn-Hilliard phase field system, the artificial compressibility method without artificial pressure boundary condition, an explicit-implicit treatment of nonlinear terms, and the addition of several key stabilization terms. This scheme is proven uniquely solvable per time step and unconditionally stable. A range of 2D and 3D numerical simulations, including accuracy tests, stability tests, interface pinch off, one or two non-isothermal air bubbles rising, Rayleigh-Taylor instability, and thermal plumes, are carried out to illustrate the model and algorithm's features and broad applicability.

Department(s)

Mathematics and Statistics

Publication Status

Full Text Access

Keywords and Phrases

Artificial compressibility method; Invariant energy quadratization method; Natural convection,; Unconditional energy stability

International Standard Serial Number (ISSN)

0045-7825

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Elsevier, All rights reserved.

Publication Date

01 Apr 2026

Included in

Mathematics Commons

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