Page 185 - TransAT_Tutorial_Manual

TransAT Tutorial Manual 4.5. Spillway

Domain

• Click the Domain & Grid tab and set the following values for the domain boundaries in
the Domain section.

X min [m] : 0.2
X max [m] : 25.7
Y min [m] : 0.75
Y max [m] : 5.0
Z min [m] : 0.5
Z max [m] : 2.335

Grid
A uniform mesh will be used as a basis.

• Enter the following grid parameters in the Grid section
Nx: 41 , Cell Ratio : 1.20 , Maximal Ratio : 2
Ny: 26 , Cell Ratio : 1.00 , Maximal Ratio : 1
Nz : 11 , Cell Ratio : 1.00 , Maximal Ratio : 1

Refinements will be performed in the zones of interest in the Customized refinement. Here
a very coarse mesh is used, and without refining it we would end up with only 3 cells in the
pipe in X direction. By slightly refining the mesh at the flow entrance section and where the
solid geometry is changing we can improve the results of the simulation. Open Customized
refinement and create new X-axis as a range type starting at X=0.2 and ending at X=15m.

Blocks
If you want to run the simulation on more than 1 processor then you can split the domain.
E.g. in order to use 4 processors the domain can be split in X and Y directions. In order to
set it up click on icon and set number of new blocks as 2 for X and Y direction. This will
create a domain split into 4 blocks. Now the simulation can run on up to 4 processors since every
processor can handle one or several blocks.

BCs Tab

• Select the BCs tab

Creating Boundary Conditions:
In this test case, a wall is at YMIN and ZMIN, pressure outflows at YMAX, XMIN and XMAX.
Symmetry boundary condition is applied at ZMAX. Note an inlet boundary condition for water
will be modelled here via pressure outflow boundary condition by employing backflow property.

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