# Simple umsh 8 cubes input

These example inputs showcase the unstructured mesh based geometry and interface capabilities in Serpent 2.

The problem geometry is a cube with coordinates [-150, 150]x[-150, 150]x[-150, 150] divided into an inner region inside [-100, 100]x[-100, 100]x[-100, 100] and a blanket region.

The inner region is also evidently cube shaped but consists of 8 sub-regions:

- Areas with positive x (+,?,?) have a larger material density (affects the nuclide densities in macroscopic cross sections).
- Areas with positive y (?,+,?) have a larger temperature (affects the temperatures of microscopic cross sections).
- Areas with positive z (?,?,+) have a larger U-233 content (affects the material composition).

In the following sections this geometry is created in several different ways:

- Using the normal Serpent geometry definitions with separate materials for all 8 regions.
- Using the unstructured mesh based geometry definition with separate materials for all 8 regions.
- Using the normal Serpent geometry definitions with temperature and density data brought in using the unstructured mesh based interface.
- Using the unstructured mesh based geometry definition with attached temperature and density data for the materials.

## Contents

## Traditional way

The "traditional" way of defining a geometry with multiple materials at multiple densities and temperatures is to create a separate material for each of the temperature and density combinations. As this example has two different nuclide compositions we end up with 2^{3} = 8 separate materials. This input creates the geometry by splitting the inner region into eight sub-regions using the coordinate planes. The correct material is then filled into each octant. The temperature and density data are specified in the material card.

### input-file

set title "8 cubes hexahedron test, CSG geo" % --- Boundary of geometry: surf 2 cuboid -150 150 -150 150 -150 150 % --- Boundary at infinity surf 3 inf % --- yz-plane surf yzPlane px 0.0 % --- xz-plane surf xzPlane py 0.0 % --- xy-plane surf xyPlane pz 0.0 % --- Cube with two metre edge length: surf 2metreCube cuboid -100 100 -100 100 -100 100 % --- Geometry based on the normal CSG-model cell HiHiHi 0 fuelHiDHiTHiU yzPlane xzPlane xyPlane -2metreCube cell HiLoHi 0 fuelHiDLoTHiU yzPlane -xzPlane xyPlane -2metreCube cell HiHiLo 0 fuelHiDHiTLoU yzPlane xzPlane -xyPlane -2metreCube cell HiLoLo 0 fuelHiDLoTLoU yzPlane -xzPlane -xyPlane -2metreCube cell LoHiHi 0 fuelLoDHiTHiU -yzPlane xzPlane xyPlane -2metreCube cell LoLoHi 0 fuelLoDLoTHiU -yzPlane -xzPlane xyPlane -2metreCube cell LoHiLo 0 fuelLoDHiTLoU -yzPlane xzPlane -xyPlane -2metreCube cell LoLoLo 0 fuelLoDLoTLoU -yzPlane -xzPlane -xyPlane -2metreCube % --- Blanket cell around the eight cubes cell 11 0 blanket 2metreCube -2 % --- Outside the geometry cell 20 0 outside 2 % --- Black BC set bc 1 % --- Fuel salts: % --- Material for cube at (+,+,+) corner (umsh cell 0) mat fuelHiDHiTHiU -4.10 tmp 1200.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cube at (+,-,+) corner (umsh cell 1) mat fuelHiDLoTHiU -4.10 tmp 600.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cube at (+,+,-) corner (umsh cell 2) mat fuelHiDHiTLoU -4.10 tmp 1200.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Material for cube at (+,-,-) corner (umsh cell 3) mat fuelHiDLoTLoU -4.10 tmp 600.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Material for cube at (-,+,+) corner (umsh cell 4) mat fuelLoDHiTHiU -2.05 tmp 1200.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cube at (-,-,+) corner (umsh cell 5) mat fuelLoDLoTHiU -2.05 tmp 600.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cube at (-,+,-) corner (umsh cell 6) mat fuelLoDHiTLoU -2.05 tmp 1200.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Material for cube at (-,-,-) corner (umsh cell 7) mat fuelLoDLoTLoU -2.05 tmp 600.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Blanket material mat blanket -0.10 rgb 50 250 50 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Run parameters: set pop 5000 200 20 % --- Geometry plot: plot 1 500 500 10 plot 1 500 500 -10 % --- Mesh plots: mesh 10 1 500 500 mesh 1 500 500 % --- Power level: set power 8.0

## Unstructured mesh based geometry

The geometry can be also defined using the irregular geometry card **solid 1**. This is of minor use here since the geometry in this case is easy to define using the normal constructive solid geometry definitions. The inner region is still created using eight separate materials but this time the geometry cells are based on the unstructured mesh definition.

### input-file

set title "8 cubes hexahedron test" % --- Boundary of geometry: surf 2 cuboid -150 150 -150 150 -150 150 % --- Boundary at infinity surf 3 inf % --- OpenFOAM mesh based geometry (universe 1, bg universe 2) % Search mesh split condition is 5 cells % Search mesh has maximum of two levels with maximum of 2^n % cells per level solid 1 1 2 5 2 2 2 "./constant/polyMesh/points" "./constant/polyMesh/faces" "./constant/polyMesh/owner" "./constant/polyMesh/neighbour" "./constant/polyMesh/materials" % --- Blanket cell in universe 2 (background universe) cell 11 2 blanket -3 % --- Geometry consists of mesh-based universe and background universe cell 19 0 fill 1 -2 % --- Outside the geometry cell 20 0 outside 2 % --- Black BC set bc 1 % --- Fuel salts: % --- Material for cube at (+,+,+) corner (umsh cell 0) mat fuelHiDHiTHiU -4.10 tmp 1200.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cube at (+,-,+) corner (umsh cell 1) mat fuelHiDLoTHiU -4.10 tmp 600.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cube at (+,+,-) corner (umsh cell 2) mat fuelHiDHiTLoU -4.10 tmp 1200.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Material for cube at (+,-,-) corner (umsh cell 3) mat fuelHiDLoTLoU -4.10 tmp 600.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Material for cube at (-,+,+) corner (umsh cell 4) mat fuelLoDHiTHiU -2.05 tmp 1200.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cube at (-,-,+) corner (umsh cell 5) mat fuelLoDLoTHiU -2.05 tmp 600.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cube at (-,+,-) corner (umsh cell 6) mat fuelLoDHiTLoU -2.05 tmp 1200.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Material for cube at (-,-,-) corner (umsh cell 7) mat fuelLoDLoTLoU -2.05 tmp 600.0 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Blanket material mat blanket -0.10 rgb 50 250 50 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Run parameters: set pop 5000 200 20 % --- Geometry plot: plot 1 500 500 10 plot 1 500 500 -10 % --- Mesh plots: mesh 10 1 500 500 mesh 1 500 500 % --- Power level: set power 8.0

### ./constant/polyMesh/points-file

"./constant/polyMesh/points" follows the unstructured mesh points file-format.

27 (1 -1 -1) (1 0 1) (0 0 -1) (0 1 1) (1 1 0) (1 0 0) (0 0 0) (0 1 0) (1 1 -1) (1 0 -1) (0 0 1) (0 1 -1) (1 -1 1) (0 -1 1) (1 -1 0) (0 -1 0) (1 1 1) (0 -1 -1) (-1 1 1) (-1 0 1) (-1 1 0) (-1 0 0) (-1 1 -1) (-1 0 -1) (-1 -1 1) (-1 -1 0) (-1 -1 -1)

### ./constant/polyMesh/faces-file

"./constant/polyMesh/faces" follows the unstructured mesh faces file-format.

36 4(5 6 7 4) 4(14 15 6 5) 4(15 25 21 6) 4(6 21 20 7) 4(7 6 10 3) 4(15 13 10 6) 4(17 15 6 2) 4(2 6 7 11) 4(5 1 10 6) 4(9 5 6 2) 4(23 2 6 21) 4(6 10 19 21) 4(3 10 1 16) 4(13 12 1 10) 4(24 13 10 19) 4(19 10 3 18) 4(8 9 2 11) 4(9 0 17 2) 4(2 17 26 23) 4(11 2 23 22) 4(1 5 4 16) 4(5 9 8 4) 4(5 14 0 9) 4(1 12 14 5) 4(21 19 18 20) 4(25 24 19 21) 4(26 25 21 23) 4(23 21 20 22) 4(4 7 3 16) 4(7 20 18 3) 4(11 22 20 7) 4(8 11 7 4) 4(13 15 14 12) 4(15 17 0 14) 4(25 26 17 15) 4(24 25 15 13)

## Traditional geometry + unstructured mesh based interface

The number of separate material definitions that are needed can be reduced to two by bringing in the temperature and density data via the multi-physics interface. The two nuclide compositions still have to be separated into their own materials. This input creates the geometry by splitting the inner region into eight sub-regions using the coordinate planes. The correct material is then filled into each octant. The temperature and density data are specified in the material card.

set title "8 cubes hexahedron test" % --- Boundary of geometry: surf 2 cuboid -150 150 -150 150 -150 150 % --- Boundary at infinity surf 3 inf % --- yz-plane (not needed) %surf yzPlane px 0.0 % --- xz-plane (not needed) %surf xzPlane py 0.0 % --- xy-plane surf xyPlane pz 0.0 % --- Cube with two metre edge length: surf 2metreCube cuboid -100 100 -100 100 -100 100 % --- Geometry based on the normal CSG-model cell HiHiHi 0 fuelHiU xyPlane -2metreCube cell HiLoHi 0 fuelLoU -xyPlane -2metreCube % --- Blanket cell around the eight cubes cell 11 0 blanket 2metreCube -2 % --- Outside the geometry cell 20 0 outside 2 % --- Black BC set bc 1 % --- Temperature and density information from interface ifc "./type8.ifc" % --- Fuel salts: % --- Material for cubes at (?,?,+) mat fuelHiU -4.10 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cubes at (?,?,-) mat fuelLoU -4.10 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Blanket material mat blanket -0.10 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Run parameters: set pop 5000 200 20 % --- Geometry plot: plot 1 500 500 10 plot 1 500 500 -10 % --- Mesh plots: mesh 10 1 500 500 mesh 1 500 500 % --- Power level: set power 8.0

Here the interface file "./type8.ifc" has been linked to the main input file. The contents of this interface file using the type 8 interface format are presented here:

8 fuelHiU 1 ./0/volpower -1 600 5 3 2 2 2 ./constant/polyMesh/points ./constant/polyMesh/faces ./constant/polyMesh/owner ./constant/polyMesh/neighbour ./constant/polyMesh/materials ./0/rho 1 ./0/T 1 ./constant/polyMesh/map

## Unstructured mesh based geometry and interface

In this input file both the geometry (material information) and the temperature and density information are brought in using the **solid 3** input card, which uses the type 9 multi-physics interface format.

This is the suggested way to define the material, temperature and density distributions if the geometry is to be created based on the unstructured mesh **and** temperature and density data is to be brought in using the same unstructured mesh. If no temperature and density distributions are needed the geometry can be created separately using the **solid 1** input card. If the geometry can be created using the normal CSG definitions the temperature and density fields can be brought in using the type 7 or type 8 multi-physics interface format.

set title "8 cubes hexahedron test, solid 3" % --- Boundary of geometry: surf 2 cuboid -150 150 -150 150 -150 150 % --- Boundary at infinity surf 3 inf % --- OpenFOAM mesh based geometry (universe 1, bg universe 2) % Search mesh split condition is 5 cells % Search mesh has maximum of two levels with maximum of 2^n % cells per level solid 3 "./type9.ifc" % --- Blanket cell in universe 2 (background universe) cell 11 2 blanket -3 % --- Geometry consists of mesh-based universe and background universe cell 19 0 fill 1 -2 % --- Outside the geometry cell 20 0 outside 2 % --- Black BC set bc 1 % --- Fuel salts: % --- Material for cubes at (?,?,+) mat fuelHiU -4.10 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Material for cubes at (?,?,-) mat fuelLoU -4.10 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 1.425 % --- Blanket material mat blanket -0.10 Li-7.06c 77.50 F-19.06c 167.50 Th-232.06c 19.65 U-233.06c 2.85 % --- Run parameters: set pop 5000 200 20 % --- Geometry plot: plot 1 500 500 10 plot 1 500 500 -10 % --- Power level: set power 8.0

The contents of the interface file follow the type 9 multi-physics interface format:

9 1 2 1 ./volpower -1 600 5 3 2 2 2 ./constant/polyMesh/points ./constant/polyMesh/faces ./constant/polyMesh/owner ./constant/polyMesh/neighbour ./constant/polyMesh/materials ./0/rho 1 ./0/T 1 ./constant/polyMesh/map