please i need help
 

simulation of inviscid compressible flow over cylinder. using FLUENT 6.3

i have a problem in { Drag convergence } wrong results .

THE important Steps that I did in FLUENT :
1-operating pressure =0 pascal
2-Boundary condition_pressure Far-field :MACH=0.4 and pressure calculated from Isentropic relation at MACH=0.4 . and temperature was calculated.
3-solver_Density based .
4-Refrence value: I have a problem at this step.
5-Results - wrong in DRAG CONVERGENCE

Please i need help , i do not know where is wrong step .

thank you