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-   -   warning "pressure corrections limited in 1540604 cells in region FLUID" (http://www.cfd-online.com/Forums/star-ccm/103373-warning-pressure-corrections-limited-1540604-cells-region-fluid.html)

fisicas1 June 18, 2012 17:07

warning "pressure corrections limited in 1540604 cells in region FLUID"
 
I have the output: "pressure corrections limited in 1540604 cells in region FLUID"

What can I do?

abdul099 June 18, 2012 19:47

Well, that depends on when that message appears and for how long. Usually it indicates the initialization is bad or there are too high pressure / velocity gradients in your domain.
When it's right at the beginning and your case keeps running and the message disappears after some (hundered) iterations, I would ignore it.
When the number drops to some few cells where the pressure correction was limited, I would ignore it.
When the case crashes right at the beginning, try a better initialization.
When it crashes after some iterations but the number of cells drops, try to reduce the under relaxation factors.
When the message still occurs after a lot of iterations, check your boundary conditions and your mesh.

fisicas1 June 19, 2012 13:48

thanks but I want to simulated a pipe with internal fluid, with these real datas: Pin(Pa),Tin (C), m (kg/s), Pout (Pa), Tout (C)

Pin=3.517 MPa
Tin=204 C


Tout=242 C
Pout=3.5083 Mpa

I do not know exactly the best option for my initialization wit my fluid, inlet and outlet. I used this inicial condition:

1║ my fluid:
Reference Values:

References Pressure:3.517 MPa

Inicial condition:

Pressure: 3.517 MPa
S Temperature: 204 C
Velocity:0.3146 m/s
2║ inlet-->velocity inlet
S Temperature: 204 C
Turbulence Intensity:0.037
Turbulent length Scale:4mm
Velocity Magnitude:0.3146 m/s
3║Outlet-->Pressure
Pressure:0mpa
Static Temperature:242 C
Turbulent length Scale:4mm
Turbulent viscosity ratio: 10

is the best way to set the inicial condition?

abdul099 June 19, 2012 21:02

It looks suspicious to me that the reference pressure is that high. You should consider, all pressure settings in Star-CCM+ are relative to the reference pressure. So setting a reference pressure of 3.517 MPa and an initial pressure of 3.517 would result in an absolute initial pressure of 7.034 MPa. So I think, you meant a reference pressure of about 1 bar?

Anyway, it is still unclear when your issue occurred. Was it right after starting the simulation, or was it after some iterations? If so, after how many iterations?

fisicas1 June 19, 2012 21:39

i have seted a reference pressure of 0.1 MPa (0.5 and 1MPa) and an initial pressure of 3.517 would result in an absolute initial pressure of 4.734 MPa, only wit 9 interation (20, 50) and it run stopped because IAPWS-IF97 outside range Tout, frist momet BIGGSTAB DID NOT CONVERGE.

Do you have any idea? I used good table, velocity. I do not know ....

thanks for your post


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