Fluid Block

Block used to add charged and neutral fluids to a simulation. A fluid in Vorpal obeys the same initial and boundary conditions as a Field. As with a Field, initial and boundary condition blocks Initial and Boundary Conditions are nested within the Fluid blocks.

Fluid Kinds


Works with VSimPA license.

A charged, cold, relativistic fluid. The velocity is updated using an upwinding advection. The density is updated using a finite volume approach with the velocity found from upwinding. In both cases, alternating direction is used.

coldRelFluid Parameters

charge (real, default -1.6e-19)

Charge of charge carrier for the fluid.

mass (real, default 9.1e-31)

Mass of the charge carrier for the fluid.

advectMomentum (integer, default = 1 (true))

Whether to advect the momentum.

accelerate (integer, default = 1 (true))

Whether to accelerate momentum.

convectDensity (integer, default = 1 (true))

Whether to convect density.

weightCurrents (integer, default = 1 (true))

Whether to weight currents.

correctDensity (integer, default = 0 (false))

Whether to apply second-order density corrections.



Works with VSimPD license:

A neutral, scalar-pressure fluid based on the algorithm described in pages 361 to 362 of Laney’s Computational Gasdynamics [Lan98].

eulerFluid Parameters

ratioSH (real)

Ratio of specific heats; affects the pressure calculation.

epsilon (real)

Value of epsilon for the fluid.


Works with VSimPA and VSimPD licenses.

(Non-dynamic) gas to be simulated.

neutralGas Parameters

gasKind (string, no default value)

Type of gas represented; used for interaction processes such as ionization, negative ion detachment, etc. The available values for gasKind will vary depending on the type of interaction. For more information on available gaskinds, please see Working with neutralGas Fluids and the gasKind Parameter.

dumpTrack (string, default = false)

Track the energy, momentum, and number of events for electron/gas interactions (including elastic, excitation, and ionization interactions). The results are written into separate h5 files. For example, when tracking an excitation interaction with dumpTrack, the additional output fields are *_ExcitationErgFld, *_ExcitationMomFld, and *_ExcitationEvtFld, where * is the name of the neutralGas block. The units of the energy field are eV, the units of the momentum field are MKS, and the units of the event field are the unitless number of events per cell. This option requires a corresponding Monte Carlo collision block to describe the various interactions.

constantDensity (string, default = false)

This flag will determine whether or not the fluid density is depleted or augmented via reaction processes.

numMacroPPCRxns (integer, default = 1)

The effective number of macro particles per cell used when performing collisions using the Reaction framework. This will only have an effect if kinetic species reacting with or produced by the reactions are variable weight. If particles are constant weight then the fluid’s effective weight will be the same.

See Also

Initial and Boundary Conditions