Case Check
Check the case file and make sure there are no reported issues.
– Use Run Calculation > Check Case
– Any potential problems with the case setup will be raised in the case check panel if there are no problems this panel will not appear. In this case there is a recommendation to check the reference values for the force monitors. Since we have already set these we can ignore this warning.
Save the case file.
– File > Save Project (if running under workbench)
Run Calculation
-Although the calculation is ready to compute, It is good practice (but not strictly necessary) to run the FMG and then check the coarse FMG solution before starting the main calculation iterations.
-Set the number of requested iterations to zero, and press ‘Calculate’.
-Check the pressure and velocity contours to make sure that no spurious values are predicted.
-Go to ‘Graphics and Animations in the LHS tree, choose ‘Contours’ and ‘Set Up’
-Choose Contours of Pressure > Static Pressure and ‘Filled’
-Display. If you need to autoscale the display press <control> A
-Zoom in as required.
-Examine the min and max reported values.
-Repeat for Contours of Velocity> Mach Number.
-There are no spurious results from the FMG, so proceed to the main calculation.
-Return to ‘Run Calculation’ in the LHS tree.
-Change the number of windows to three (for the residual, drag and lift monitors that we set up earlier).
-Request 900 iterations.
-‘Calculate’
After 900 iterations the calculation has fully converged.
– Note that the CFL has been updated during the calculation in a number of stages, ramping up from 5 to 200 as we requested. This can be seen in the CFL window and the effect on the residuals is also evident. By the end of the calculation the residuals have converged well and are no longer changing. The drag and lift monitors are also stable.
Post Processing [FLUENT]
Select ‘Graphics and Animations’ in the LHS menu
Examine the contours of static pressure.
– Turn off ‘Filled’ to just display the contour lines.
– Adjust the Levels to increase the number of contour lines.
The contour will display in the active window (click a window to activate). Alternatively, use the drop down menu to return the display to a single window as shown here
Plot contours of Velocity > Mach Number and notice that the flow is now locally supersonic.
Select ‘Plots’ in the LHS menu.
Plot Pressure Coefficient along the top and bottom airfoil surfaces.
Compare experimental pressure coefficient plots which we can import and plot here alongside the numerical prediction.
Click on ‘Load File’ and browse for the files in your directory.
Once loaded, plot the CFD and experimental Cp plots together.
A good agreement can be seen.
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