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Passive Scalar Sources

Passive scalar sources can be used to simulate the propagation of spiecies like smoke from a burning car in a garage or the diffusion of dust or pollutants in a tunnel.

Preparation

Passive scalar sources are implemented in the Passive Scalar Transport analysis. Please, see the documentation page for this type of analysis Passive Scalar Transport. The passive scalar source has to be assigned to a volume, defined through a geometry primitive (cartesian box, sphere and cylinder) or a cell zone (see the Surface Refinement section of Mesh settings for further details on how to create a cell zone). It is generally good practice to refine the mesh in the vicinity of the source, in order to better capture the dynamics of the flow and avoid convergence problems.

Creation of a passive scalar source

In the simulation tree navigate to “Advanced Concepts” and add a “Passive Scalar Source”. Two types of sources are supported:

Passive scalar source

This type of source is defined by a flux, which may be interpreted as a concentration per unit time. The user needs to specify the flux value and select the region previously defined.

Volumetric passive scalar source

This type of source is defined by a flux per unit volume. Consequently, the actual flux is implicitly computed using the volume of the source region. As in the first case, the user needs to specify the specific flux value and select the region previously defined.

Defining a passive scalar source

In the Figure above, a passive scalar source is defined using a sphere as geometry primitive (highlighted in blue). A flux of 0.2 1/s is prescribed.

The full setup is contained in this project:

Passive scalar sources reference project