CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CD-adapco (http://www.cfd-online.com/Forums/cd-adapco/)
-   -   v4 & AMG warning msg (http://www.cfd-online.com/Forums/cd-adapco/56393-v4-amg-warning-msg.html)

more work December 19, 2007 05:56

v4 & AMG warning msg
 
Hi! I'm now running v4 but using trim mesh created in v3. It ran quite well earlier without porous media. However, now in a model containing porous media I got this warning msg below but only after 45 iterations onwards. Kindly someone let me what this warning message means.

45 2.75E-01 1.00E+00 7.00E-01 -- -- -- -- 1.03E+05-6.73E+13 4.40E-01 -- -- -- -- FINISH ITERATION NO. 45 CPU time is 306.86 Elapsed time is 307.11

46 3.82E-01 1.00E+00 2.81E-01 -- -- -- -- 3.04E+05-1.05E+14 6.09E-01 -- -- -- -- FINISH ITERATION NO. 46 CPU time is 311.89 Elapsed time is 312.14 WARNING: Ap = 0 on multigrid level 1, nRows = 49184, blockSize = 1

AMG coarsening halted. WARNING: Ap = 0 on multigrid level 1, nRows = 49974, blockSize = 1

AMG coarsening halted. WARNING: Ap = 0 on multigrid level 1, nRows = 50823, blockSize = 1

AMG coarsening halted.

47 2.92E-01 1.00E+00 6.90E-01 -- -- -- -- 2.73E+05-1.06E+14 1.67E+00 -- -- -- -- FINISH ITERATION NO. 47 CPU time is 400.92 Elapsed time is 401.17 WARNING: Ap = 0 on multigrid level 1, nRows = 49011, blockSize = 1

AMG coarsening halted. WARNING: Ap = 0 on multigrid level 1, nRows = 50353, blockSize = 1

AMG coarsening halted. WARNING: Ap = 0 on multigrid level 1, nRows = 49831, blockSize = 1

AMG coarsening halted.


rcm March 7, 2012 00:34

This is due to small un conected surfaces in mesh
To rectify this right click and select repair surface in Representation >> remeshed surface, which you can find below plots

A new window called Surface Prepration Options will pop up. Click OK

In the side pane, select mode as "Edit conected surfaces" from the drop down and click start diagonosis

it will display more than one line of surface groups in a table.
Highlight and delete the small unconnected surfaces and close the window.

Select generate volume mesh to remesh

fshak92 March 28, 2012 08:42

Quote:

Originally Posted by rcm (Post 348025)
This is due to small un conected surfaces in mesh
To rectify this right click and select repair surface in Representation >> remeshed surface, which you can find below plots

A new window called Surface Prepration Options will pop up. Click OK

In the side pane, select mode as "Edit conected surfaces" from the drop down and click start diagonosis

it will display more than one line of surface groups in a table.
Highlight and delete the small unconnected surfaces and close the window.

Select generate volume mesh to remesh

Do we have to regenerate a volume mesh after using 'remove invalid cells in region' ? or it is compulsory just after using surface repair?
Thank you in advance.

rcm March 28, 2012 09:56

yes. generate volume mesh and switch on cell quality remediation

fshak92 March 29, 2012 04:47

Quote:

Originally Posted by rcm (Post 351939)
yes. generate volume mesh and switch on cell quality remediation

Thank you for your answer. :)

Just a question.After removing some cells by 'remove invalid cells' ,first i did not regenerate volume mesh.So we should expect the residual isn't changed.
but it was changed a lot.
What does it mean?

Thank you in advance.


All times are GMT -4. The time now is 07:24.