Page 389 - TransAT_Tutorial_Manual

TransAT Tutorial Manual 9.2. Forced Convection in an Isothermal Pipe

Figure 9.17: Computational grid (k = kBoundaryCell layer)

Given that all cells have the same dimension in the x- and z- directions, Eq. 9.5 is equivalent to
the following equation
P
u ii T ii vol ii
Ω i
(9.6)
T bulk = P
u ii vol ii
Ω i
with vol ii the cell-volume. To integrate over the cross-section corresponding to a specific wall
cell, the getWallBoundaryCellIndex and the convert1DindexTo3D are used to get the indices of
cells in the cross-section.

First, the 1D-index of the wall cell in the block is accessed through the getWallBoundaryCellIndex
then it is converted into a 3D-index to get the indices of the cells in the cross-section

// Get wall cell 1D-index in block
iiWallCell = getWallBoundaryCellIndex(nb, icell, "direction_top");
// Get 3D-indexing of wall cell
convert1DindexTo3D(nb,iiWallCell,iBoundaryCell,jBoundaryCell,kBoundaryCell);

The cells belonging to the cross-section in block iblock have fixed coordinates in the first and third
directions. Their indices in the first and third directions are respectively equal to iBoundaryCell
and kBoundaryCell and their index in the second direction varies between 2 and nj - 4 which
corresponds the set of internal cells as shown in Figure 9.17. For more details, see the Cell-data
access and filtering section in the TransAT User Manual .
Eq. 9.5 is then transcribed as follows in the streamwise output function:

// Compute bulk temperature
// Initialise numerator and denominator for bulk temperature computation

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