[sajad_abasi]

hi to all.
im simulationg a transient model.i want to change resistance of porous domain relative to mass flow in a manner that when massflow decraese the porous resistance also decrease.i defined an an "AV" in following form:
LIBRARY:
&replace ADDITIONAL VARIABLE: cvr
Option = Definition
Tensor Type = SCALAR
Units = [m^-1 ]
Update Loop = TRANS_LOOP
Variable Type = Specific
END
END
the initial value of cvr is 20000,but in the next iteration when i set the resistance of porous in porous domain by CEL expression "cvr" it assumes that resistance is near zero.it works with no error but give wrong results.
how can i use the value of "cvr" in passed time step for this time step?
thanks