Outputs

Unsteady Solution Data

Field Data

Unsteady field data represents the time evolution of an unsteady field at the time step iteration interval specified by out_interval in solver_params.inp. All unsteady field data is written to working_dir/unsteady_field_results, and currently comes in five flavors: primitive state output, conservative state output, source term output, heat release output, and RHS term output. With the exception of the heat release output, all have the same general form: a NumPy binary file containing a single NumPy array with three dimensions. The first dimension is the number of variables, the second is the number of cells in the computational mesh, and the third is the number of time steps saved in the output file. The primitive state, conservative state, and RHS term output have the same number of variables, equal to the number of governing equations (3 + num_species - 1), while the source term only has (num_species - 1) variables. Heat release output only has two dimensions, the first for the number of cells and the second for the number of time steps.

Primitive state field data is saved if prim_out = True and has the prefix sol_prim_*. Conservative state field data is saved if cons_out = True and has the prefix sol_cons_*. Source term field data is saved if source_out = True and has the prefix source_*. RHS term field data is saved if rhs_out = True and has the prefix rhs_*. Heat release field data is saved if hr_out = True and has the prefix heat_release_*.

Unsteady field data may have three different main suffixes, depending on solver parameters: *_FOM for an unsteady full-order model simulation, *_steady for a “steady” full-order model simulation (see Running in “Steady” Mode) for details), or *_ROM for a reduced-order model simulation. An additional suffix, *_FAILED, is also appended if the solver fails (solution blowup). Thus, the conservative field results for a failed ROM run would have the name sol_cons_ROM_FAILED.npy, while a successful run would simply generate sol_cons_ROM.npy.

Probe Data

Probe/point monitor data represents the time evolution of an unsteady field variable at a single finite volume cell. Probe locations are specified by probe_locs in solver_params.inp, and the fields to be measured are specified by probe_vars. Valid options for probe_vars can be found in Input Parameter Index. Probe measurements are taken at every physical time step. Data for each probe is saved to a separate file in working_dir/probe_results. Each has the format of a NumPy binary file containing a single two-dimensional NumPy array. The first dimension is the number of variables listed in probe_vars plus one, as the physical solution time is also stored at each iteration. The second dimension is the number of physical time steps for which the simulation was run.

The name of each probe begins with probe_*, and is followed by a list of the variables stored in the probe data. Finally, the same suffixes mentioned above are applied depending on the solver settings: *_FOM`, ``*_steady, and *_ROM. Again, if the solver fails, the suffix *_FAILED will also be appended. Finally, the 1-indexed number of a the probe will be appended to the end of the file. For example, the second probe monitoring the velocity and momentum of a “steady” solve which fails will have the file name probe_velocity_momentum_2_steady_FAILED.npy.

Restart Files

All restart file data is stored in working_dir/restart_files. Please refer to Restart Files for details on the formatting and contents of restart files.

Visualizations

During simulation runtime, PERFORM is capable of generating two types of plots via matplotlib: field plots and probe monitor plots. If vis_show = True in solver_params.inp, then these images are displayed on the user’s monitor. If vis_save = True, they are saved to disk. The interval of displaying/saving the figures is given by vis_interval. Each figure corresponds to a single instance of vis_type_X, within which there may be several plots. Each probe figure corresponds to a single probe, from which multiple probed variables may be extracted.

All saved images are PNG images stored within working_dir/image_results.

Field Plots

Field Plots display instantaneous snapshots of the entire field with the field data plotted on the y-axis and cell center coordinates plotted on the x-axis.

Field plots save an instantaneous snapshot of the field plots at the interval set by vis_interval. These are stored within a subdirectory following the same pattern given to field data files, except the prefix of the directory is given by working_dir/image_results/field_*. Within this subdirectory, individual images have the prefix fig_*, followed by the number of the image in the series of expected image numbers to be generated by a given run. If a simulation terminates early any field plots that were expected to be generated will not be generated.

Probe Plots

Probe plots display the entire time history of the probed data up to the most recent plotting interval reached by the simulation, with the probed variable data plotted on the y-axis and time plotted on the x-axis.

A single figure is saved to disk for a given probe figure. It if first written after vis_interval time steps, after which the same file is overwritten at the interval specified by vis_interval. The names of probe plots follow the same pattern given to the probe data files (except with the file extension *.png, of course).