Trying to run transient analysis, the run stop after

the first iter. message is like

STEP UVEL VVEL WVEL MASS T EN DISS ENTH U V W P TE ED T

1 1.93E-02 2.41E-05 6.43E-02-4.74E-02 9.69E-01 7.81E+03 1.36E+04 -1.86E+00-6.49E+00 1.63E+02 1.28E+03 2.24E+02 1.99E+06 6.02E+02 Warning - starwatch daemon is not registered, no information sent to starwatch.

*** ERROR #076 *** NEGATIVE DENSITIES FOUND AT MORE THAN 100 CELLS. RUN STOPPED

what wrong of my model set-up

Hi

Does your time step meet the courant equation?

(Cr = (v * t)/L ,where Cr = Courantnumber of a cell, v = velocity of fluid in this cell (compressible: velocity of fluid + speed of sound), t = time step and L is the length of this cell)

The max. Cr shouldn't exceed 50 - 100.

If you do have moving mesh (events module) you may try to reduce the time step length.

Another thing to you and to the others who has the same problem you may try the MARS differencing scheme and don't ask me why because I don't know why but it works.