Overview of capabilities
This page provides an overview of the main capabilities of the code.
Grids, fixed and variable weight DSMC
| 0D | 1D | |
|---|---|---|
| Fixed-weight DSMC | ✅ | ✅ |
| Variable-weight DSMC | ✅ | ❌ |
Currently, simulations are either 0D (spatially homogeneous) or on a uniform 1D grid. For 1D simulations, specular and diffuse reflection models are available (along with a mixture of the two via an accommodation coefficient).
Collisions
The No-Time-Counter (NTC) approach of Bird (1994) is implemented for fixed-weight DSMC. The variable-weight NTC approach of Schmidt and Rutland (2000) is implemented for variable-weight DSMC. Event splitting (Oblapenko et al. (2022)) is implemented for neutral-electron interactions.
Fokker-Planck collisions
As an alternative to DSMC, one can use the stochastic Fokker-Planck algorithm to simulate the particle collisions. Currently, the linear Fokker-Planck model of Gorhi, Torrilhon, and Jenny (2011) is implemented for fixed-weight particles.
| Linear | Cubic | |
|---|---|---|
| Fixed-weight Fokker-Planck | ✅ | ❌ |
| Variable-weight Fokker-Planck | ❌ | ❌ |
Particle merging algorithms
The following particle merging algorithms are available for variable-weight DSMC simulations:
- A grid-based merging algorithm as described in Oblapenko et al. (2020) (see also Vranic et al. (2015))
- The octree merging algorithm of Martin and Cambier (2016)
- A Non-Negative Least Squares (NNLS)-based merging approach described in Oblapenko (2024)
Cross-sections
The Variable-Hard Sphere (VHS) model is implemented for collisions of neutral particles. For neutral-electron collisions, LXCat data in XML format needs to be provided for the elastic scattering and electron-impact ionization cross-sections. Currently, only isotropic scattering is implemented for neutral-electron collisions.
Inelastic collisions
In flows with neutrals, ions, and electrons, electron-impact ionization is supported. Variable weight DSMC simulations also support the Event Splitting (ES) collision algorithm of Oblapenko et al. (2022).
External fields
Acceleration of charged particles by a constant electric field is supported.
I/O
The code assumes the TOML format for the particle and VHS interaction data. XML is used for the LXCat data. Output of the computed macroscopic properties is in NetCDF4 format.