Piecewise linear interface calculation (PLIC) schemes have been extensively employed in the Volume-of-Fluid (VOF) method for interface capturing in numerical simulations of multiphase flows. Dynamic overset meshes can be especially useful in applications involving component motions and complex geometric shapes. The basic idea of the overset mesh is the flow field interpolation within the overlapped region between the background mesh and the body mesh. Most of the overset interpolation methods are designed for continuous flow variables. The acceptor cell value is evaluated by using a weighted average of its donors.   
The weighting factors are obtained by using different algebraic methods, such as the averageValue, injection and inverseDistance schemes.  
A geometric interpolation scheme of the VOF field in overset meshes for the PLIC-VOF method has been proposed in this study.   
The VOF value of an acceptor cell is evaluated in a geometric way with the reconstructed interfaces from the corresponding donor elements.  
The geometric interpolation scheme computes the intersections between the acceptor and the liquid part of all donors and then normalizes their summations by the acceptor volumes.  
It should be noted that the geometric interpolation scheme has been built on the framework of OpenFOAM which is an open-source C++ toolbox.  
Test cases employing dual-circle (sphere) and dual-Pi inside a unit square/cube with a rotational velocity field have been performed to demonstrate the accuracy of the proposed overset interpolation scheme by comparison with other algebraic ones from the built-in Foam-Extend overset library for both 2D and 3D simulations, respectively.   
Two liquid regions with the shape of Pi or circle (sphere) are located in the background and body meshes symmetrically. Advection tests with an imposed solenoidal velocity field have been applied to the four interpolation schemes.  
The same mesh size has been applied to the background mesh and body mesh with three different mesh sizes tested in quadrilateral/hexahedron overset meshes.   
With the mass conservation satisfied, shape reconstruction accuracies have been evaluated by comparing the shape errors quantitatively in all four schemes.  
Due to the design symmetry of the computational domain, shape errors are calculated at the half and one period.   
Details of the comparative study on the performances of the four interpolation schemes will be reported.


A Comparative Study of Interpolation Schemes in Overset Meshes for the Plic-Vof Method in Multiphase Flows

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.