Real world problems are typically multi-material, combining materials such as gases, liquids and solids that have very different properties. The material interfaces may be fixed in time or can be a part of the solution, as in fluid-structure interactions or air-water dynamics, and therefore move and change shape. In such problems the computational mesh may be non-conformal to interfaces due to complexity of these interfaces, presence of small fractions of materials, or because the mesh does not move with the flow, as in the arbitrary Lagrangianâ€“Eulerian (ALE) methods. In order to solve problems of interest on such meshes, interface reconstruction methods are usually used to recover an approximation of material regions within the cells. For a cell intersecting multiple material regions, these approximations of contained subregions can be considered as single-material subcells in a local mesh that we call a minimesh. In this paper, we discuss some of the requirements that discretization methods have on topological information in the resulting hierarchical meshes and present an approach that allows incorporating the buildup of sufficiently detailed topology into the nested dissections based PLIC-type reconstruction algorithms (e.g. Volume-of-Fluid, Moment-of-Fluid) in an efficient and robust manner. Specifically, we describe the X-MOF interface reconstruction algorithmmore »

- Publication Date:

- Report Number(s):
- LA-UR-17-31096

Journal ID: ISSN 0045-7930

- Grant/Contract Number:
- AC52-06NA25396

- Type:
- Accepted Manuscript

- Journal Name:
- Computers and Fluids

- Additional Journal Information:
- Journal Name: Computers and Fluids; Journal ID: ISSN 0045-7930

- Publisher:
- Elsevier

- Research Org:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

- Sponsoring Org:
- USDOE

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 97 MATHEMATICS AND COMPUTING; Computer Science; Mathematics; Multi-material problems; Interface reconstruction

- OSTI Identifier:
- 1440485

```
Kikinzon, Evgeny, Shashkov, Mikhail Jurievich, and Garimella, Rao Veerabhadra.
```*Establishing mesh topology in multi-material cells: enabling technology for robust and accurate multi-material simulations*. United States: N. p.,
Web. doi:10.1016/j.compfluid.2018.05.026.

```
Kikinzon, Evgeny, Shashkov, Mikhail Jurievich, & Garimella, Rao Veerabhadra.
```*Establishing mesh topology in multi-material cells: enabling technology for robust and accurate multi-material simulations*. United States. doi:10.1016/j.compfluid.2018.05.026.

```
Kikinzon, Evgeny, Shashkov, Mikhail Jurievich, and Garimella, Rao Veerabhadra. 2018.
"Establishing mesh topology in multi-material cells: enabling technology for robust and accurate multi-material simulations". United States.
doi:10.1016/j.compfluid.2018.05.026.
```

```
@article{osti_1440485,
```

title = {Establishing mesh topology in multi-material cells: enabling technology for robust and accurate multi-material simulations},

author = {Kikinzon, Evgeny and Shashkov, Mikhail Jurievich and Garimella, Rao Veerabhadra},

abstractNote = {Real world problems are typically multi-material, combining materials such as gases, liquids and solids that have very different properties. The material interfaces may be fixed in time or can be a part of the solution, as in fluid-structure interactions or air-water dynamics, and therefore move and change shape. In such problems the computational mesh may be non-conformal to interfaces due to complexity of these interfaces, presence of small fractions of materials, or because the mesh does not move with the flow, as in the arbitrary Lagrangianâ€“Eulerian (ALE) methods. In order to solve problems of interest on such meshes, interface reconstruction methods are usually used to recover an approximation of material regions within the cells. For a cell intersecting multiple material regions, these approximations of contained subregions can be considered as single-material subcells in a local mesh that we call a minimesh. In this paper, we discuss some of the requirements that discretization methods have on topological information in the resulting hierarchical meshes and present an approach that allows incorporating the buildup of sufficiently detailed topology into the nested dissections based PLIC-type reconstruction algorithms (e.g. Volume-of-Fluid, Moment-of-Fluid) in an efficient and robust manner. Specifically, we describe the X-MOF interface reconstruction algorithm in 2D, which extends the Moment-Of-Fluid (MOF) method to include the topology of minimeshes created inside of multi-material cells and parent-child relations between corresponding mesh entities on different hierarchy levels. X-MOF retains the property of being local to a cell and not requiring external communication, which makes it suitable for massively parallel applications. Here, we demonstrate some scaling results for the X-MOF implementation in Tangram, a modern interface reconstruction framework for exascale computing.},

doi = {10.1016/j.compfluid.2018.05.026},

journal = {Computers and Fluids},

number = ,

volume = ,

place = {United States},

year = {2018},

month = {5}

}