Post-processing

When the analysis is completed and the message "Process … started on … has finished." has been displayed, we can proceed to visualise the results by pressing Post-process.

For details on the result visualisation not explained here, please refer to the Postprocessing chapter of the previous examples and to the Postprocessor manual or online help.

Below some results of the analysis carried out are shown.

GiD hardcopy output

Figure 31 Velocity module distribution

GiD hardcopy output

Figure 32 Pressure distribution

GiD hardcopy output

Figure 33 Stream lines and velocity distribution on some cuts

We can verify the quality of the results by comparing the calculated period of the vortex shedding with experimental data.

The computed period of the phenomenon can can be evaluated by visualising the time evolution of the forces acting on the cylinder. This can be done using the "Forces Graph" option of the menu "View Results" (see Figure 34).

Figure 34 Forces Graph menu option

In Figure 35 the evolution of the pressure vertical force (PFy option) on the cylinder (between t=106.2s and t=119s) is shown (the values are given in standard units N):

Figure 35 shows that the period of the process is about 6.4 seconds. This is to be compared with the experimental value of T = 5.98 s reported in [13].

The calculated period leads to a Strouhal number of Str = 0.16 which is  very close to the experimental value obtained in [13]andabout 6% below the numerical value reported in [14].

These results can be improved by recalculating the problem using a finer mesh.

Figure 35 Forces Graph window