CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM (http://www.cfd-online.com/Forums/openfoam/)
-   -   What has happend to the edges of domain (http://www.cfd-online.com/Forums/openfoam/65575-what-has-happend-edges-domain.html)

yijin_li June 18, 2009 23:10

What has happend to the edges of domain
 
Hi,

I use rhoSimpleFoam to simulate a blade of gas turbine.

This is the picture of the simulation result.

http://user.qzone.qq.com/76247914/ph...FlyYK9YkAAA!!/

What has happend to the edges of domain?

Is there something wrong with the cyclic boundary conditions?

yijin_li June 18, 2009 23:13

http://b17.photo.store.qq.com/http_i...08ad9f4fc5adc1

yijin_li June 18, 2009 23:36

checkMesh
 
checkMesh

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = constant

Time = constant

Mesh stats
points: 160248
faces: 454912
internal faces: 429824
cells: 147456
boundary patches: 6
point zones: 0
face zones: 0
cell zones: 0

Number of cells of each type:
hexahedra: 147456
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 0

Checking topology...
Boundary definition OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface topology
row_1_BLADE 6912 7128 ok (non-closed singly connected)
row_1_SHROUD 4608 4856 ok (non-closed singly connected)
row_1_HUB 4608 4856 ok (non-closed singly connected)
row_1_OUTFLOW 1536 1617 ok (non-closed singly connected)
row_1_INFLOW 768 825 ok (non-closed singly connected)
row_1_PER 6656 6930 ok (non-closed singly connected)

Checking geometry...
This is a 3-D mesh
Overall domain bounding box (0.6063716664 -0.09400876493 -0.06) (0.8094251252 0.05889179552 0.163938279)
Mesh (non-empty) directions (1 1 1)
Mesh (non-empty, non-wedge) dimensions 3
Boundary openness (-2.53523191331e-19 3.19783473277e-19 4.97898165194e-19) Threshold = 1e-06 OK.
Max cell openness = 1.90379145707e-15 OK.
Max aspect ratio = 335.077993397 OK.
Minumum face area = 8.94726575451e-10. Maximum face area = 9.81471952282e-05. Face area magnitudes OK.
Min volume = 5.60997898251e-14. Max volume = 2.49818970804e-07. Total volume = 0.00251046768668. Cell volumes OK.
Mesh non-orthogonality Max: 50.1995248971 average: 14.3396737008 Threshold = 70
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 1.5808312121 OK.

Mesh OK.

End

sega June 19, 2009 03:28

Sorry, I can't see any pictures of your domain ...

yijin_li June 19, 2009 04:15

This is the picture
 
1 Attachment(s)
This is the picture

sega June 19, 2009 04:34

Yes this looks strange. Can you provide a picture of the actual mesh?

yijin_li June 19, 2009 04:43

this is grid
 
1 Attachment(s)
this is grid

yijin_li June 19, 2009 04:47

shroud grid
 
1 Attachment(s)
this is shroud grid

sega June 19, 2009 04:59

From my experience with interFoam I can tell that sometimes slightly skewed hex cells give rise to problems with the pressure.

This may be an explanation for the pressure field in proximity of the bend.

Using corrected schemes for snGrad solved the problem within interFoam.
Maybe you even have to increase the value of nonOrthogonalCorrectors, which triggers the number of correction loops within the solution of the momentum equation.

But this is not explaining the pressure region at the outlet.

yijin_li June 19, 2009 07:19

decoupling problem
 
3 Attachment(s)
Is this decoupling problem?

sega June 19, 2009 07:47

Quote:

Originally Posted by yijin_li (Post 219872)
Is this decoupling problem?

I don't understand your question. What do you mean with 'decoupling problem'?

And what happend to your domain in the first picture?

yijin_li June 19, 2009 08:31

Quote:

Originally Posted by sega (Post 219878)
I don't understand your question. What do you mean with 'decoupling problem'?

And what happend to your domain in the first picture?


I changed relTol from 0 to 0.05 in fvSolution, than the first picture is the result.

I found that there are some fluctuating of pressure near the outlet boundary.
I think that something wrong with pressure and velocity.


All times are GMT -4. The time now is 06:59.