Postprocessing

HiFiLES can output several data formats for postprocessing.

RAW DATA

Raw field data can be written in either Tecplot binary (.plt) or Paraview ASCII (.vtu in serial, *.pvtu in parallel) data formats. The choice of Tecplot/Paraview output is determined by the parameter 'write_type' in the input file. In parallel runs outputting Paraview data, the *.pvtu files are header files containing a list of *.vtu files, which are stored in a subdirectory created by the code. Each *.vtu file corresponds to a separate mesh partition. Tecplot data files are also written per-partition but are written directly to the run location rather than a subdirectory.

The displayed mesh consists of the computational mesh with each element subdivided into sub-elements. The number of sub-elements is controlled by the input parameter 'p_res'. For example, in a quad mesh there will be (p_res-1)*(p_res-1) sub-elements. Note that the mesh points do not correspond to the solution points. Note also that the solution may be discontinuous across element boundaries. Both Paraview and Tecplot use linear interpolation between point values to display a continuous field inside an element. Finally, beware that high-order simulations (e.g. p=5) can produce very large file sizes! Support for Paraview binary output will be added in future, this should reduce file size somewhat.

DIAGNOSTIC FIELDS

Several diagnostic fields can be computed in a simulation and output as raw data. See (https://github.com/HiFiLES/HiFiLES-solver/wiki/Input-File) for options.

HISTORY FILE

Residuals, integrated forces, lift/drag coefficients and compute time are written to an ASCII text file named 'history.plt'. Data is added every t timesteps determined by the input parameter 'monitor_res_freq'. You can plot this data directly in Tecplot or write your own script. Additional quantities are added to the history file if integral quantities (such as integrated kinetic energy) are selected in the input file.

PRESSURE AND FRICTION COEFFICIENTS

Coefficients of pressure and friction are written to a series of files named 'cp__p

.dat' in the subdirectory 'force_files' (created by the code). Here, stands for the timestep and

is the partition. Each file is a list of the coefficients at each position along the x axis. In 3D only the x position is given but in future the y position will also be given. Note that the code assumes that the x axis is aligned with the flow direction.