KNOWN ISSUE: Variables available for user defined particle drag
Unintentionally, there is a limit on the variables that can be used in the Particle User Routine for specifying particle drag. The variables are limited to: fluid and particle velocity, velocity fluctuations, slip velocity, particle Reynolds number, particle diameter and fluid density. For example, particle volume fraction is not available.
There is an error in the CFX-Solver routine that parses the list of variable names provided by the user.
Use the User Fortran routine for particle momentum sources.
ANSYS CFX Release 12.1. A custom executable for ANSYS CFX Release 12.0 is available on request.