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A hybrid finite‐element–volume‐of‐fluid method for simulating free surface flows and interfaces
Author(s) -
Mashayek F.,
Ashgriz N.
Publication year - 1995
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/fld.1650201205
Subject(s) - volume of fluid method , finite element method , mechanics , free surface , surface tension , finite volume method , coalescence (physics) , boundary value problem , advection , boundary element method , computer science , flow (mathematics) , physics , mathematics , engineering , structural engineering , mathematical analysis , quantum mechanics , astrobiology , thermodynamics
A numerical technique is developed for the simulation of free surface flows and interfaces. This technique combines the strength on the finite element method (FEM) in calculating the field variables for a deforming boundary and the versatility of the volume‐of‐fluid (VOF) technique in advection of the fluid interfaces. The advantage of the VOF technique is that it allows the simulation of interfaces with large deformations, including surface merging and breaking. However, its disadantage is that is solving the flow equations, it cannot resolve interfaces smaller than the cell size, since information on the subgrid scale is lost. Therefore the accuracy of the interface reconstruction and the treatment of the boundary conditions (i.e. viscous stresses and surface tension forces) become grid‐size‐dependent. On the other hand, the FEM with deforming interface mesh allows accurate implementation of the boundary conditions, but it cannot handle large surface deformations occurring in breaking and merging of liquid regions. Combining the two methods into a hybrid FEM‐VOF method eliminates the major shortcomings of both. The outcome is a technique which can handle large surface deformations with accurate treatment of the boundary conditions. For illustration, two computational examples are presented, namely the instability and break‐up of a capillary jet and the coalescence collision of two liquid drops.