If Specify mass flow rate is selected from the Particle release specification list in the physics interface Particle Release and Propagation section, the Mass Flux subnode is available from the context menu (right-click the Wall parent node) or from the Physics toolbar, Attributes menu. The Mass Flux subnode uses accumulated variables on each boundary element in the selection of the parent node to calculate the mass flux of particles at a boundary.

Select a Type: Mass flux or Normal mass flux (the default). For Mass flux accumulated variables are defined for components of the mass flux vector. For Normal mass flux one accumulated variable is defined for the normal mass flux in each boundary element.