Various kinds of Piecewise Linear Interface Calculations (PLIC) are commonly used in Computational Fluid Dynamics (CFD) for multiphase flows. Here, a new method is proposed to calculate the interface size for CFD simulations. This PLIC method with the modifier, Analytic Size Based [method], (PLIC-ASB), being that the calculation requires a symbolic equation and no approximation or numerical methods. The primary advantage of the PLIC-ASB is maintaining a sharp interface and providing for physics-based (not iterative or empirically derived factors) mass transfer due to the cell-by-cell accuracy. Along with the sharp interface, this method leads to precise interface displacements and suppresses parasitic velocities; altogether, this means an accurate model of the temperature distribution near the interface can be achieved. The PLIC-ASB method was compared directly against the VOF gradient method (most prevalent PLIC in multiphase simulations). Static testing for accuracy on various geometric shapes expressed as the color function on representative grids of cells. The PLIC-ASB had a better result than the VOF gradient method, with an average relative error of 3% and 13%, respectively. Spherical bubble growth simulations were performed with customized ANSYS-Fluent. Both interface calculation methods were tested. Foremost, the PLIC-ASB method produced experimentally and theoretically anticipated results. Parasitic velocities were problematic in the VOF gradient method simulations but only minor with the use of PLIC-ASB. Further, a trend of accuracy improving with reduced cell size was found with the PLIC-ASB, whereas no trend was present with the VOF-gradient method. The PLIC-ASB method has the characteristic limitations of any PLIC method, most notably requiring a straight-line approximation to suitably represent the multiphase interface; however, the straightforward implementation and accuracy make broad adoption reasonable.
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Department, Program, or Center
Mechanical Engineering (KGCOE)
Shipkowski, S.P., Perez-Raya, I., 2023. Precise and analytical calculation of interface surface area in sharp interfaces and multiphase modeling. International Journal of Heat and Mass Transfer 202, 123683. https://doi.org/10.1016/j.ijheatmasstransfer.2022.123683
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