# AcuGetNodeSubset

Extract a subset of AcuSolve nodal output to disk.

## Syntax

acuGetNodeSubset [options]

## Type

AcuSolve Post-Processing Program

## Description

AcuGetNodeSubset is a post-processing utility used to extract a subset of nodal output from the AcuSolve solution database at user-given node locations.

In the following, the full name of each option is followed by its abbreviated name and its type. For a general description of option specifications, see Command Line Options and Configuration Files. See below for more individual option details:

help or h (boolean)
If set, the program prints a usage message and exits. The usage message includes all available options, their current values, and the place where each option is set.
problem or pb (string)
The name of the problem is specified via this option. This name is used to generate input file names and extracted surface file names.
run_id or run (integer)
Number of the run in which the extraction is requested. If run_id is set to 0, the last run in the working directory is assumed.
element_sets or cnns (string)
Comma-separated list of element sets to extract nodal data from. These are the names specified as the user-given name of the SURFACE_OUTPUT commands in the input file. If element_sets is set to _all, all output sets are included into the force computation.
surfaces or osis (string)
Comma-separated list of surface_output sets. These are the names specified as the user-given name of the SURFACE_OUTPUT commands in the input file. If surface_integral_output_sets is set to _all, all output sets are used to extract the nodal data.
node_file or files (string)
Comma-separated list of node files containing node IDs to extract the dataset from.
time_steps or ts (string)
Comma-separated list of time steps to be translated. The comma-separated fields have the general range format beg:end:inc, where :end:inc and :inc are optional. beg specifies the first time step in the range. It may be either a given time step, as specified by a number, the letter F (or f) requesting the first available time step. end is the last time step in the range. It may be either a time step number or the letter L (or l) requesting the last available time step. If end is missing, the range is assumed to simply represent a single time step (that is, end = beg and inc = 1). inc is the increment that ranges from beg to end. It may be either a number or the letter A (or a) requesting all available time steps in the range. If :inc is missing, it is assumed to be one. The range may also be specified by the single letter A (or a), requesting all available time steps. This is equivalent to F:L:A.
nodal_output_vars or outv (string)
Comma-separated list of nodal_output variables to be translated. The list may include:
Table 1.
Variable (abbr) Fields Description
density (dens) 1 Density, only for flow = compressible_navier_stokes.
velocity (vel) 3 Velocity vector
mach_number (mach) 1 Mach number, only for flow = compressible_navier_stokes.
pressure (pres) 1 Pressure
temperature (temp) 1 Temperature
relative_humidity 1 Relative humidity
dewpoint_temperature 1 Dewpoint temperature
humidity_film_thickness 1 Humidity film thickness
species (spec) nSpecs Species
field nFields Field values. For multi_field = levelset and multi_field = algebraic_eulerian, the field values correspond to volume fractions, and are named as volume_fraction-"fieldname". For multi_field = advective_diffusive, the field values correspond to mass fraction.
levelset (levelset) 1 Levelset
eddy_viscosity (eddy) 1 Turbulence eddy viscosity
kinetic_energy (tke) 1 Turbulence kinetic energy
eddy_frequency (tomega) 1 Turbulence eddy frequency
sqrt_eddy_period (tg) 1 Inverse of the square root of eddy frequency
dissipation_rate (teps) 1 Turbulence dissipation rate
intermittency (tintc) 1 Turbulence intermittency
transition_re_theta (treth) 1 Critical momentum thickness Reynolds Number
surface_y_plus (yp) 1 y+ on turbulence walls
surface_film_coefficient (film) 1 Convective heat transfer coefficient on turbulence walls.
wall_shear_stress (wall_shear) 3 Wall shear stress on turbulence walls.
viscoelastic_stress (vest) 6 Viscoelastic stresses
mesh_displacement (mesh_disp) 3 Mesh displacement vector
mesh_velocity (mesh_vel) 3 Mesh velocity vector

where nSpecs is the number of species as given in the EQUATION command in the input file. Note that the problem must contain the requested variable in order for it to be translated. For example, the parameter turbulence in the EQUATION command must be set to a value other than none in order for eddy_viscosity to be available. The list of variables is sorted in the order given in the above table. If nodal_output_vars is set to _all, all available variables are translated. The surface_y_plus, surface_film_coefficient and wall_shear_stress are non-zero only on surface nodes given by TURBULENCE_WALL, or alternatively by SIMPLE_BOUNDARY_CONDITION of type wall. Note that the surface_film_coefficient is computed even if there is no temperature equation. However, all relevant fluid material models must include specific heat and conductivity models. It should also be noted that eddy_frequency and sqrt_eddy_period only appear when using the k-omega based turbulence models. The dissipation_rate variable only appears when using the k-epsilon based turbulence models, and intermittency and transition_re_theta only appear when using the turbulence transition models.

output_fields or fields (string)
Comma-separated list to specify the output fields that are printed to the output files. Specified by combining the abbreviated values id,crd,time,data into a comma-separated list, for example, crd,data or id,crd,data or id,crd,time,data.
output_file_format or ofmt (enumerated)
Specifies the output format of the files written to disk. ASCII for text readable space delimited file, binary for compressed binary format.
verbose or v (integer)
Set the verbose level for printing information to the screen. Each higher verbose level prints more information. If verbose is set to 0 (or less), only warning and error messages are printed. If verbose is set to 1, basic processing information is printed in addition to warning and error messages. This level is recommended. verbose levels greater than 1 provide information useful only for debugging.

## Examples

Consider the extraction of the thermal solution from a single element set at multiple time points:
acuGetNodeSubset -cnns M1S1P1 outv temperature -ts 100:500:100
or alternatively the options may be put into the configuration file Acusim.cnf as follows:
acuGetNodeSubset.pb=battery acuGetNodeSubset.cnns=M1S1P1
acuGetNodeSubset.outv=temperature acuGetNodeSubset.ts=100:500:100
The following will be printed to the standard output of the terminal:
acuGetNodeSubset:
acuGetNodeSubset:  Opening the AcuSolve solution data base
acuGetNodeSubset:  Problem <battery> directory <ACUSIM.DIR> runId <0>
acuGetNodeSubset:
acuGetNodeSubset:  Opened run id <1>
acuGetNodeSubset:
acuGetNodeSubset:  Processing element set <M1S1P1>
acuGetNodeSubset:
acuGetNodeSubset:  Compiling the unique node list
acuGetNodeSubset:
acuGetNodeSubset:  Processing step <100>
acuGetNodeSubset:  Writing data to file <battery.subset_step000100.out>
acuGetNodeSubset:  Processing step <200>
acuGetNodeSubset:  Writing data to file <battery.subset_step000200.out>
acuGetNodeSubset:  Processing step <300>
acuGetNodeSubset:  Writing data to file <battery.subset_step000300.out>
acuGetNodeSubset:  Processing step <400>
acuGetNodeSubset:  Writing data to file <battery.subset_step000400.out>
acuGetNodeSubset:  Processing step <500>
acuGetNodeSubset:  Writing data to file <battery.subset_step000500.out>
acuGetNodeSubset:
acuGetNodeSubset:  Total elapsed time <96.8489789963> seconds
acuGetNodeSubset:

The above example produces five output files containing the simulated series of nodal (spatial dependent) temperatures contained for the element set with the name “M1S1P1”.

The file contains the following columns with example output quantities:
 CoordinateX CoordinateY CoordinateZ Temperature -1.5499e-01 -1.225e-01 -2.396e-01 3.00586e+02
Consider the extraction of the thermal solution from a single surface set at a single time point:
acuGetNodeSubset -osis Cells_M1S8P7 -outv temperature -ts 100
or alternatively the options may be put into the configuration file Acusim.cnf as follows:
acuGetNodeSubset.pb=battery
acuGetNodeSubset.cnns=M1S8P7
acuGetNodeSubset.outv=temperature
acuGetNodeSubset.ts=100
The following will be printed to the standard output of the terminal:
acuGetNodeSubset:
acuGetNodeSubset:  Opening the AcuSolve solution data base
acuGetNodeSubset:  Problem <battery> directory <ACUSIM.DIR> runId <0>
acuGetNodeSubset:
acuGetNodeSubset:  Opened run id <1>
acuGetNodeSubset:
acuGetNodeSubset:  Processing surface output <Cells_M1S8P7>
acuGetNodeSubset:    Surface output <Cells_M1S8P7> matches <Cells_M1S8P7>
acuGetNodeSubset:
acuGetNodeSubset:  Compiling the unique node list
acuGetNodeSubset:
acuGetNodeSubset:  Processing step <100>
acuGetNodeSubset:  Writing data to file <battery.subset_step000100.out>
acuGetNodeSubset:
acuGetNodeSubset:  Total elapsed time <21.0808241367> seconds

The above example produces five output files containing the simulated series of nodal (spatial dependent) temperatures contained for the element set with the name “M1S1P1”.