[viking]

Hi there,

i am using cfx 14.5 and an icem mesh.
the simulation case is as follows:

filled cylinder with helium, valve closed. Valve blocks flow from helium filled cylinder into 'vacuum' pipe (means real low density and pabs like 10 Pa).

then the valve opens (conditional connection interface plus using moving mesh for the large, 16 mm, opening distance).

the problem is now: in initial conditions there is no flow in the domains, e.g. subsonic conditions. but if the valve opens, we will get high flow rates like mach 3 (in helium mach# is about 1000 m/s). and this seems to be transsonic flow.

So what can we do to have this transition from 0mach to 3mach flow?
is it wrong to use the transsonic model from the beginning?

kind regrads
sebastian