Post-processing

Once the message "Process … started on … has finished." is displayed, we can visualise the final results by pressing Post-process.

Note that the problem must still be loaded; should this not be the case we first have to open the problem files.

Note that the intermediate results can be shown in any moment of the process even if the calculations are not finished.

On first entering the post-processing module, two windows - View Style and View Results - are accessible through the Windows menu (see Figure 15).

                        View Style

Figure 15 Accessing the “View style” and "View results" windows

The View Style or Select & Display Style window allows the user to select, which elements of the mesh to be post-processed, and how the results will be represented. In this window (see Figure 16) the label Mesh 1 makes reference to the mesh of the Control Surface, whereas Set 4 refers to the body and Set 12 and Set 13 to the rest of surfaces and lines.

View Results

This window allows the end-user to choose the result to be represented and the way this result will be displayed (see Figure 17).

Figure 16 Select & Display Style or View window

Figure 17 View Results window

Results Visualisation

As most of the results will be visualised over a cross section only, rather than over the whole control volume, we have to proceed by cutting the mesh at the desired position. To do the cut, follow the instructions of Figure 18.

Figure 18 Cut Plane menu option

The cut plane will be perpendicular to the view drawn on the screen. By selecting the nodes of the mesh you can introduce points, either with the mouse or by introducing their co-ordinates manually in the command line. In this example we will select a cut plane parallel to the original orientation of the control volume (XY-plane).

In the Select and display Style window the cut planes will appear defined together with the previously explained entities (Set 12, Mesh 11 etc.) as Cut1, Cut2… All the entities can be turned "on" and "off". By leaving only the cuts "on" we can plot and visualise the results over the cross section.

First we will visualise the velocity distribution over the cut plane by plotting the iso-contours of the x and the y velocity components (see Figure 19). This will be achieved by choosing the following options in the View results window:

Steps:              (usually the last time step of the selection)

View:               Contour Fill

Results:            velocities

Component:     x-component

y-component

The postprocessing image can then be saved as a screenshot of the current window by using its "camera" icon from the graphical menu.

 
GiD hardcopy outputGiD hardcopy output

Figure 19 Contour lines of the x-component (left) and y-component (right) of the velocity vector

For more details on the postprocessing steps, please refer to the GiD user manual (ref. [6]), or to the online help from the Help menu.