Use the Number Density Calculation feature to compute the spatial number density of particles in the selected domains. The number density is computed by counting the particles in each mesh element in the selected domains, then dividing by the mesh element volume. In 2D the number of particles is divided by the mesh element area, whereas in 2D axisymmetric models it is divided by the element volume of revolution. Optionally the average velocity of particles in each element can also be computed.

When the Particle release specification is set to Specify release times, you may enter a value or expression for the Number multiplication factor nn (dimensionless). The default is 1. This acts as a scaling factor when counting the particles in each mesh element; if the value is changed to 10, for example, the number density of particles will be the number of particles in each mesh element, divided by the mesh element volume and multiplied by 10. If the Enable macroparticles check box is selected in the physics interface Additional Variables section, the text field for n is not shown; instead, the weighting factor is initialized by the particle release features.

Select the Compute average velocity check box to compute the average velocity of particles in each mesh element.