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nanoFluidX Command Reference
nanoFluidX commands and parameters with examples.
Visualization Surfaces
Visualization surfaces are used to represent walls or boundaries for post-processing and visualization purposes.

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What's New
View new features for nanoFluidX 2026.
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nanoFluidX Tutorials
Discover nanoFluidX functionality with interactive tutorials.
Pre-processing
Create a nanoFluidX model using SimLab.
nanoFluidX Command Reference
nanoFluidX commands and parameters with examples.
- Simulation
  Defines the global simulation parameters, such as simulation time and output settings.
- Domain
  In the domain section, the global definitions for the simulation are set, such as the number of dimensions and the numerical reference parameters.
- Dye Regions
  Used for fluid motion tracking.
- Extractors
  Import an .stl file and use it as a sampling surface for variable fields. This surface can be visualized during post-processing and can enable various advanced post-processing. The feature supporting this ability is called an extractor.
- Frame Suite
  This section expands on frame suite set up sliding frame for water wading applications.
- Inlet Regions
  Defines inlet region parameters.
- Impose Regions
  Define any number of regions to alter/prescribe velocity, acceleration, porous media or temperature.
- Kernel
  The spline function used to interpolate quantities and derivatives is called a kernel in SPH. To define the kernel according to the initial particle configuration, the spacing must be set here.
- Motions
  Wall boundary particles can be moved during a simulation with a prescribed motion. Depending on the type of the imposed motion, different values must be defined.
- Load Balancing
  The dynamic load-balancing (LB) capability allows the nanoFluidX code to redistribute the work load among the GPUs, which generally improves the overall performance.
- Outlet Regions
  Outlet regions mimic the behavior of outlet and simple outlet using a combination of removal and extended regions. They allow particles of any phase to be removed from anywhere within the computational domain.
- Phases
  In the phases section the material parameters are defined for different SPH components.
- Visualization Surfaces
  Visualization surfaces are used to represent walls or boundaries for post-processing and visualization purposes.
- Probes
  Probe particles are created in order to extract accurate post-processing information from a particular location, such as a FLUID, WALL or a MOVINGWALL phase.
- Viscosity Models
  This section describes the parameters for properly enabling various viscosity models.
Post-processing
nanoFluidX Theory Manual
Physics and theory for nanoFluidX.
nanoFluidX Validation Manual
Error and Warning Messages
This glossary contains generic messages generated by nanoFluidX, their likely causes, and possible methods to resolve the related issues.
nanoFluidX Frequently Asked Questions
This section provides quick responses to typical and frequently asked questions regarding nanoFluidX.
Bibliography
References used throughout the nanoFluidX manual.

Visualization Surfaces

Visualization surfaces are used to represent walls or boundaries for post-processing and visualization purposes.

Each surface is described as a vizsurf entry within the vizsurfs block.

Commands

vizsurfs
{
            vizsurf
        {
                vizsurf_name            "piecename"                     
                vizsurf_phase           1
                vizsurf_file            "filename"
        }

}

Definitions


Command	Contents	SI Unit Example
`vizsurf_name`	(Optional) Name of this visualization surface piece.
`vizsurf_phase`	(Optional) Vizsurf entry is ignored when the keyword is not present or the value is empty. ID of the phase from the Phases section to which this visualization surface piece belongs. Must point to a WALL or MOVINGWALL phase type.
`vizsurf_file`	(Optional) Relative or absolute path to the .stl file representing this visualization surface piece. Use of the relative path is recommended.