Fokker-Planck-Poisson kinetics: multi-phase flow beyond equilibrium

被引:5
|
作者
Sadr, Mohsen [1 ]
Pfeiffer, Marcel [2 ]
Gorji, M. Hossein [3 ]
机构
[1] Rhein Westfal TH Aachen, Applied & Computat Math, Schinkestr 2, D-52062 Aachen, Germany
[2] Univ Stuttgart, Inst Space Syst, Pfaffenwaldring 29, D-70569 Stuttgart, Germany
[3] Swiss Fed Labs Mat Sci & Technol, Lab Multiscale Studies Bldg Phys, Dubendorf, Switzerland
基金
瑞士国家科学基金会;
关键词
kinetic theory; multiphase flow; non-continuum effects; INVERTED TEMPERATURE-GRADIENT; MOLECULAR-DYNAMICS; SPINODAL DECOMPOSITION; ENSKOG EQUATION; DENSE GAS; EVAPORATION; MODEL; SIMULATION; SURFACE; CONDENSATION;
D O I
10.1017/jfm.2021.461
中图分类号
O3 [力学];
学科分类号
08 ; 0801 ;
摘要
Multi-phase phenomena remain at the heart of many challenging fluid dynamics problems. Molecular fluxes at the interface determine the fate of neighbouring phases, yet their closure far from the continuum needs to be modelled. Along the hierarchy of kinetic approaches, a multi-phase particle method is devised in this study. This approach is built closely upon the previous studies on the kinetic method development for dense gases [Phys. Fluids, vol. 29 (12), 2017] and long-range interactions [J. Comput. Phys., vol. 378, 2019]. It is on this background that the current work on Fokker-Planck-Poisson modelling of multi-phase phenomena is initiated. Molecular interactions are expressed via stochastic forces driven by the white noise, coupled to the long-range attractions. The former is local and pursues diffusive approximation of molecular collisions, whereas the latter takes a global feature owing to mean-field forces. The obtained Fokker-Planck-Poisson combination provides an efficient work flow for physics-driven simulations suitable for multi-phase phenomena far from the equilibrium. Besides highlighting the computational efficiency of the method, various archetypical and complex problems ranging from inverted temperature gradients between droplets to spinodal decomposition are explored. Detailed discussions are provided on different characteristics of the droplets dispersed in low/high density background gases; including the departure of heat fluxes from Fourier's law as well as droplets growth in spinodal phases.
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页数:40
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