# Command Reference

nanoFluidX commands and parameters with examples.

nanoFluidX uses two files to setup a simulation. A configuration file, which defines all relevant simulation parameters and phase properties, and a geometry file, that defines the initial discretization of the problem with particles.

## Configuration File (.cfg)

The configuration file (*.cfg) defines all relevant parameters to start a simulation including the geometry definition, phase properties, and numerical parameters.
Note:
• Vector components are placed in quotation marks.
• It is recommended that all input files (.prtl and .cfg) are in ASCII format.
• All names in the .cfg file and file names outside (in the case of working folders), should be alphanumeric ASCII. The only exceptions are the .stl geometry file names.
Each section of the configuration file contains data and explanations of possible contents for each variable. If a parameter has a default value, it can be omitted in the configuration file and is set internally. Variables without default values must be set. Motion definitions, for example, do not need to be set if motion is not defined.
Attention: nanoFluidX uses SI units for all of its parameters with the exception of rotational vector definition, specified in desired units, and phase shift angles for conrod and oscillate motions, specified in degrees.

## Particle File (.prtl)

The particle file (*.prtl) defines the particles used in the simulation and their phase assignment.

The file structure (geometry definition) is a table with the position of the particles and the assigned phase number.
1 0.0 0.0 0.0
1 0.0 0.0 0.1
1 0.0 0.1 0.0
2 0.0 0.2 0.0
…

The geometry file can also contain an initial velocity (for FLUID phase type) or wall velocity field (for WALL phase type). This alternative format is enabled by using the inputfileReadMode command in the Domain Parameters section. When set to INPTFL_PXYZUVW, the required geometry file must have three columns for velocity components in the X, Y, and Z direction.

Simple geometries are defined manually or via script. For industrial cases using complex geometries, the SimLab pre-processor is used to generate the initial geometry files. More information on using SimLab can be found in the SimLab tutorials or during a nanoFluidX training.