- I am working on the Appendices part of the AIAA MAO conference paper.
- RAE 2822, Mach=0.750, Rec=6.2 x 106 , alpha=3.19 deg. case (taken from the AGARD report, case 10) seems to be the most complicated case in terms of the strength of the shock and the size of the flow separation among all the RAE 2822 cases that have experimental data. We will focus on this case in order to confirm the discretization error results obtained in the transonic diffuser case (the lack of grid convergence for the strong shock case).
- A new grid (Figures 1, 2, 5, and 6) has been generated for the RAE 2822 airfoil (Grid 4). This is the finest grid to be used in the computations. This grid is obtained by using grid 3, which was taken from the NPARC validation archive. While creating grid 4, the mesh points of grid 3 were preserved and the additional points were obtained by linear interpolation so that the new points are on the mid-point of the lines connecting the neighboring nodes of grid 3 (grid doubling). In order to obtain the additional points on the airfoil surface, again linear interpolation was used. Initially cubic-spline fits were used to get the points on the airfoil surface, however some of the points obtained by this way were located below the grid lines connecting the surface points of the grid 3. This caused intersection of the coordinate lines of same family. Visual inspection of the surface points obtained by linear interpolation in the vicinity of the leading and trailing edges showed no problem (Figures 3 and 4).
- With the addition of the new grid, we have now four grid levels for the RAE 2822 case: Grid 1 (92x16 cells), Grid 2 (184x32 cells), Grid 3 (368x64 cells), and Grid 4 (736x128 cells). I am now running case 10 of the AGARD report by using these grids. The results of grid 1 (coarse), grid 2 (medium), and grid 3 (fine) were presented last week.
Figure 1. Grid 4 (736 x 128 cells) and grid 3 (368 x 64 cells)
used in the RAE 2822 airfoil computations (full view).
Figure 2. Grid 4 (736 x 128 cells) and grid 3 (368 x 64 cells)
used in the RAE 2822 airfoil computations (region in the vicinity of the
airfoil).
Figure 3. Points on the airfoil surface, near the leading edge
region. (blue points are obtained by linear interpolation).
Figure 4. Points on the airfoil surface, near the trailing edge
region. (blue points are obtained by linear interpolation).
Figure 5. Grid 4 (736 x 128 cells) and grid 3 (368 x 64 cells)
used in the RAE 2822 airfoil computations (region in the vicinity of the
leading edge).
Figure 6. Grid 4 (736 x 128 cells) and grid 3 (368 x 64 cells)
used in the RAE 2822 airfoil computations (region in the vicinity of the
trailing edge).