Using user routine USRSRC of CFX4.4 I want to set mass sources. I look into the manual, there is something dealing with variable UMDOT and UMDOTO, but still not clear for me. My questions: How should I define the dimensions of UMDOT and UMDOTO? How these variables look like? It'll be very grateful if somebody could give some detailes about the questions.

The mass source would be set in SU and SP like any other source terms, checking for IEQN to equal the equation number for Pressure (mass). The source SU will be in units of kg/s. See section 10.30.2.

Jeff

Not quite true.

You should always use SU for mass sources, even if they are -ve (sinks).

but should I add it as real value or dimensionless value, which means multipled by volume of cells? Thanks