[ticofiz]

Hello,

I have encountered a peculiar problem when I try to simulate a supersonic nozzle with Ansys Fluent 18.0. I use 3D density-based solver, Viscous SST k-omega model, constant pressure at inlet and outlet. Everything goes well in Steady state but when I switch to Transient the solution does not change or changes slightly no matter the time step. It seems that it just takes the solution obtained during the Initialization and for some reason the flow does not change. I have tried to initialize with Hybrid, with values from Inlet, Outlet, etc.
Could you please tell me what am I missing here? Have I forgotten some hidden setting or something?

Many thanks.

Update: If I do the Initialization using Hybrid mode I get a solution very close to the steady state solution that changes a bit during the simulation. I cannot see the evolution of the flow as the profile does not change much
If I do the Initialization using Standard Initialization with the Inlet parameters then I get a solution with a high value that drops fast as the time step advances until it reaches the steady state solution. Again I cannot see the evolution of the flow. Very weird stuff. I expected to see the flow evolving slowly from the inlet towards the outlet.

[ticofiz]

Hello,

I have managed to solve partially the problem. It seems that the initialization has to be done with pressure outlet parameters or with very small values for the flow parameters. It seems to be working when the inlet pressure is small and the solver is pressure-based. It diverges wildly when I increase the inlet pressure. No luck to make it work when the solver is density-based, no matter the inlet pressure. I am back where I started . Any good recipe to make it work?

Thanks

[Aristi]

Did you manage to solve this? i am encountering the same problem for a supersonic intake.