A novel volume of fluid model (VoF) called explicit volume diffusion (EVD) is developed for the simulation of interfacial flows, including those with turbulence and primary spray atomisation. The EVD model is derived by volume averaging the VoF equations over a physically-defined length scale. This introduces unclosed sub-volume flux, sub-volume stress and volume averaged surface tension force. Sub-volume fluctuations arise due to both turbulent motions and other interface dynamics which can, in general, occur in both laminar and turbulent flows. Both of these types of fluctuations are attenuated by the volume averaging process. The sub-volume flux is closed by a gradient diffusion model and involves an explicit volume diffusion coefficient that is linked to the physical length scale. The sub-volume stress closure introduces an explicit volume viscosity augmented by turbulent viscosity in turbulent flows. The volume averaged surface tension force closure is based on fractal properties of wrinkled sub-volume interfaces. These closures are evaluated through a priori analysis of resolved flow simulations for a series of two-dimensional laminar and three-dimensional turbulent interfacial shear flows. Subsequently, full EVD simulations are validated for these shear flows and for a laboratory airblast spray jet. Numerical convergence is demonstrated by keeping the physical length scale constant while reducing the numerical grid size so that numerical diffusion diminishes and becomes overwhelmed by the explicit volume diffusion. A sensitivity analysis is also conducted for variations in the physical length scale, which is compared to the boundary layer thickness on the light fluid side of the interface.
A hybrid Volume of Fluid Phase-Field method for Direct Numerical Simulations of soluble surfactant-laden interfacial flows
Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520, IEMN（里尔大学、法国国家科学研究中心、中央里尔学院、上法兰西高等工学院）；Institut Universitaire de France（法国国立高等教育学院）；Department of Chemical Engineering, Indian Institute of Technology Roorkee（印度鲁尔基理工学院化学工程系）
Interfacial dynamics and energy cascade in immiscible Rayleigh-Taylor turbulence
School of Ocean and Civil Engineering, Shanghai Jiao Tong University（上海交通大学海洋与土木工程学院）；Department of Physics, National University of Defense Technology（国防科技大学物理学院）
Direct numerical simulation of two-phase flows with surfactant-induced surface viscous effects
Imperial College London（帝国理工学院）；Hongik University（弘益大学）；Abdullah Al Salem University（阿卜杜拉·萨利姆大学）；Université Paris Saclay（巴黎-萨克雷大学）；University of Cambridge（剑桥大学）
Derivation and Efficient Entropy-Production-Rate-Preserving Algorithms for a Thermodynamically Consistent Nonisothermal Model of Incompressible Binary Fluids
