Skip to content

Latest commit

 

History

History
51 lines (36 loc) · 2.74 KB

INFO_VISU.md

File metadata and controls

51 lines (36 loc) · 2.74 KB
Raw

how to visualize the output binary files form CaNS

in addition to the binary files for visualization, CaNS now generates a log file that contains information about the saved data (see out2d.h90 and out3d.h90 for more details); this new approach uses that log file to generate the Xdmf visualization file.

the steps are as follows:

  1. after the simulation has run, copy the contents of utils/visualize_fields/gen_xdmf_easy/write_xdmf.py to the simulation data folder;
  2. run the file with python write_xdmf.py.
  3. load the generated Xdmf (*.xmf) file using paraview/visit or other visualization software.

example: how to visualize the default binary output

3D fields

when running the script write_xdmf.py we get the following prompts:

 $ python write_xdmf.py
 Name of the log file written by CaNS [log_visu_3d.out]:
 Name to be appended to the grid files to prevent overwriting []:
 Name of the output file [viewfld_DNS.xmf]:
  • the first value is the name of the file that logged the saved data;
  • the second is a name to append to the grid files that are generated, which should change for different log files to prevent conflicts;
  • the third is the name of the visualization file.

by pressing enter three times, the default values in the square brackets are assumed by the script; these correspond to the default steps required for visualizing 3D field data.

2D fields

the procedure for visualizing 2D field data that is saved by CaNS in out2d.h90 is exactly the same; it is just that the correct log file should be selected. CaNS saves by default field data in a plane of constant y=ly/2, and logs the saves to a file named log_visu_2d_slice_1.out. If more planes are saved, the user should make sure that one log file per plane is saved by CaNS (e.g. if another plane is saved, the log file written in out2d.h90 could be named log_visu_2d_slice_2.out); see out2d.h90 for more details. The corresponding steps to generate the Xdmf file would be, for instance:

 $ python write_xdmf.py
 Name of the log file written by CaNS [log_visu_3d.out]: log_visu_2d_slice_1.out
 Name to be appended to the grid files to prevent overwriting []: 2d
 Name of the output file [viewfld_DNS.xmf]: viewfld_DNS_2d.xmf

checkpoint files

A similar script also located in utils/visualize_fields/gen_xdmf_easy, named write_xdmf_restart.py, can be used to generate metadata that allows to visualize the field data contained in all saved checkpoint files:

 $ python write_xdmf_restart.py
 Name of the pattern of the restart files to be visualized [fld?*.bin]:
 Names of stored variables [VEX VEY VEZ PRE]:
 Name to be appended to the grid files to prevent overwriting [_fld]:
 Name of the output file [viewfld_DNS_fld.xmf]: