Section: io

This section deals with parameters that affect input/output to the simulation, solely the checkpoint and plot files. These inputs do not affect when these files are output, but they address file naming and high-level parameters. The “time” section controls when these files are output.

Primary location in code: amr-wind/utilities/IOManager.cpp.

io.check_file

type: String, optional, default = “chk”

If time.checkpoint_interval or time.checkpoint_time_interval is greater than zero this is the name of the checkpoint file appended with the current timestep

io.plot_file

type: String, optional, default = “plt”

If time.plot_interval or time.plot_time_interval is greater than zero this is the name of the plot file appended with the current timestep.

io.restart_file

type: String, optional, default = “”

If a string is present amr-wind will restart using the specified file in the string. This is the only argument addressing “input” of data to the simulation instead of “output”.

io.post_processing_directory

type: String, optional, default = “post_processing”

Name of the directory that will contain post processing output (e.g., sampling).

io.output_default_variables

type: Boolean, optional, default = true

Based on what fields are active in a simulation, amr-wind generates a list of variables to output to plotfiles (e.g., velocity, density, and p). If these defaults are not desired, this input argument can be set to false.

io.allow_missing_restart_fields

type: Boolean, optional, default = true

When initializing a simulation, amr-wind determines which fields are necessary based on the physics and other details in the input file. If a simulation begins with a restart file, it is possible that the restart file has fewer fields than what the new simulation needs, depending on the input arguments. This argument allows the simulation to continue despite the mismatch. If set to “false”, the simulation will abort when necessary fields are missing in the restart file.

io.outputs

type: List of strings, optional, default = “”

Add variable names to this input argument to add them to the plotfile output. These must be variables that exist in the simulation and consist of real numbers (not integers).

io.int_outputs

type: List of strings, optional, default = “”

Add variable names to this input argument to add them to the plotfile output. These must be variables that exist in the simulation and consist of integers (not real numbers).

io.derived_outputs

type: List of strings, optional, default = “”

Add derived variable names to this input argument to add them to the plotfile output. These are derived quantities that are functions of real variables that exist in the simulation. Currently, the available derived quantity definitions that operate on the velocity field are vorticity magnitude (mag_vorticity), q-criterion (q_criterion), non-dimensional q-criterion (q_criterion_nondim), and strain rate magnitude (mag_strainrate). Generic derived quantity definitions, which operate on fields specified as an argument, include the gradient operator (grad), the divergence operator (div), the Laplacian operator (laplacian), and components (components), which isolates the specified component of a field.

io.skip_outputs

type: List of strings, optional, default = “”

Add variable names to this input argument to omit them from the plotfile output. These refer to variables that are be real numbers, and this is a way to individually omit default output variables.

io.output_hdf5_plotfile

type: Boolean, optional, default = false

Flag indicating whether or not to output HDF5 plot files.

io.hdf5_compression

type: String, optional, default = “None@0”

String for requesting a particular ZFP compression in HDF5 plot files.

io.nfiles

type: Int, optional, default = 256

Number of plot and checkpoint data files per write. If the system’s IO prefers fewer or more files, this number can be modified with this option.