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-   -   Hypersonic Viscous (http://www.cfd-online.com/Forums/star-ccm/113937-hypersonic-viscous.html)

h.jaz March 1, 2013 06:40

Hypersonic Viscous
 
Hi,

I am currently using star CCM+ to model Hypersonic Flow. I used for the inviscid case and it was alright although few problems were encoutered regarding the stability of the solver which needed fine tunning of the courant number.

However, when I added viscoucity to the model the (and chose turbulent flow in my physics model). I get a floating point exception error straight away (after 2-4 iterations)?

Does any one know whether Star CCM+ can solve viscous (turbulent) Hypersonic flow? If it can do then how can I get rid of the floating point error?

Also, Do you know If the stability of the solver is an inherent problem with Star CCM+ hypersonic solver (ASUM+ FVS)?

Thanks

grad@itu March 1, 2013 14:39

Which version do you use of STAR-CCM+?
And i worked at 1,2,4,6 mach numbers around a bullet-like geometry and i dont see that kind of error.. There is no solver problem i think.. did you try other turbulent models? Spalart-Almaras can you try?

h.jaz March 6, 2013 07:54

Hi,

Thanks for your reply.

I am using Star-CCM+7.06.009.

Can I ask how you modelling the flow around the bullet like geometry? i.e. How big is your fluid block around the body? what mesh base size are you using relative to a characteristic length of the body? what is the distance you left between the base and the end of the fluid block?

Moreover, Can I ask you whether you know how to set a "continuative" boundary condition at the outlet? Because I expect my outlet flow to remain supersonic? I am currently say that the boundary at the outlet is a "pressure outlet" which I believe could be wrong modelling because I am specifying pressure on outlet to be free stream pressure.

By continuative I mean set the pressure at the outlet to be the same as the pressure corresponding to the previous cell.

Or are u aware of a suitable boundary of the outlet?

Moreover, still for the inviscid case I struggle to get good convergence in the Y & Z momentum, can you suggest how to solve this?

Your help is much appreciated.

Regard,


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