Mesh – FEST-3D

To solve a real-life problem, like flow over an airfoil, first, a domain of computation has to be defined. This domain represents the system of interest which we like to study. Now to apply a numerical method to solve the governing equation (Navier-Stokes) on this domain, it needed to be discretized. This process is not part of the FEST-3D code and it assume a predefine discretized domain(grid) will be provided as input. You can use softwares like Pointwise to generate the good quality mesh. The FEST-3D expect structured grid in the following format

Imax  Jmax  Kmax
X(1,1,1)   Y(1,1,1)   Z(1,1,1)
X(2,1,1)   Y(2,1,1)   Z(2,1,1)
X(3,1,1)   Y(3,1,1)   Z(3,1,1)
...
X(Imax,1,1)   Y(Imax,1,1)   Z(Imax,1,1)
X(1,2,1)   Y(1,2,1)   Z(1,2,1)
X(2,2,1)   Y(2,2,1)   Z(2,2,1)
...
...
X(Imax,Jmax,1)   Y(Imax,Jmax,1)   Z(Imax,Jmax,1)
X(1,1,2)   Y(1,1,2)   Z(1,1,2)
X(2,1,2)   Y(2,1,2)   Z(2,1,2)
X(3,1,2)   Y(3,1,2)   Z(3,1,2)
...
...
...
X(Imax,Jmax,kmax)   Y(Imax,Jmax,kmax)   Z(Imax,Jmax,kmax)

In the case of multi-block, as shown in Fig. 1, each process requires a separate grid file and block should be created such that every face of that block employs only a single boundary condition. For now, two different types of boundary conditions at a single face of a block is not supported by the FEST-3D.

A very simple example of grid file is given below for 2D-smooth bump test case, shown in Fig. 3:
Blocks: 2 Number of blocks in I-direction are 2. So, two files will be written: grid_00.txt for first block and grid__01.txt for second block
Imax: 3
Jmin: 2
Kmin: 2

CoarseGrid — Fig.2 Simple coarse grid for 2D smooth bump test case.

grid_00.txt

2 2 2
-1.5000e+00  2.3271e-26  0.0000e+00
 0.0000e+00  6.2500e-02  0.0000e+00
-1.5000e+00  8.0000e-01  0.0000e+00
 0.0000e+00  8.0000e-01  0.0000e+00
-1.5000e+00  2.3271e-26  1.0000e-01
 0.0000e+00  6.2500e-02  1.0000e-01
-1.5000e+00  8.0000e-01  1.0000e-01
 0.0000e+00  8.0000e-01  1.0000e-01

grid_01.txt

2 2 2
0.0000e+00  6.2500e-02  0.0000e+00
1.5000e+00  2.3271e-26  0.0000e+00
0.0000e+00  8.0000e-01  0.0000e+00
1.5000e+00  8.0000e-01  0.0000e+00
0.0000e+00  6.2500e-02  1.0000e-01
1.5000e+00  2.3271e-26  1.0000e-01
0.0000e+00  8.0000e-01  1.0000e-01
1.5000e+00  8.0000e-01  1.0000e-01

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