CFD Online URL
[Sponsors]
Home > Forums > NUMECA

urgent problem in the multi-stage multi-row computation

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   September 18, 2010, 10:27
Default urgent problem in the multi-stage multi-row computation
  #1
Member
 
Join Date: Sep 2010
Posts: 45
Rep Power: 6
BalanceChen is on a distinguished road
I generated the multi-row grid by copy and rotate an existed grid block. Thus the IGV have 8 channels and rotor have 24 channels. Then i connect them in IGG by "import IGG project". Next, the boundary condition is reset, i.e., the connecting face is set to be "ROT".
The problem is when i am going to run in fine turbo, after reading in the grid, errors go as

"CSTRDA/C1DMED: TOO MANY MERGER PAIRS( 41 > 40)

NBCMAX EXPERT PARAMETER SHOULD BE INCREASED"

I have no idea of what should i do, is there anybody come across problems like this, please help me, thx~~
BalanceChen is offline   Reply With Quote

Old   September 21, 2010, 00:14
Default
  #2
Senior Member
 
Hamid Zoka
Join Date: Nov 2009
Posts: 152
Rep Power: 7
Hamidzoka is on a distinguished road
NBCMAX is an expert parameter that can be set in NUMECA.
when you change the fine/turbo mode from "standard" to "expert"
you can find it in one of tables of "contorl variables" page, namely"integer parameters".
but i think your problem is mainly due to number of channels you 've selected. why 8 and 24? perhaps this enormous amount of mesh causes such problem. if you are to solve an steady problem, just one blade per each row will be enough. but in case an unsteady solution is desired, the best solution is to choose the lowest integer balde count ratio. e.g. a configuration of 1 to 3 is adequate for this case. this will reduce your meshing to 1/8.

Regards
Hamidzoka is offline   Reply With Quote

Old   September 23, 2010, 22:26
Default
  #3
Member
 
Join Date: Sep 2010
Posts: 45
Rep Power: 6
BalanceChen is on a distinguished road
Thank you very much for your detailed explanation, problem is figured out~
The problem i consern now is with an nonaxisymmetrical inlet flow, whole rows computation is thus needed.

Thanks again.

Regards.
BalanceChen is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Urgent problem - orthotropic material in ICEM Luk CFX 6 August 30, 2006 09:06
Valve seal problem! Urgent songxguan Main CFD Forum 0 May 11, 2006 23:04
Multiphase Problem (Urgent) Dadang CFX 4 June 21, 2004 08:46
a problem on convergence in stage interface feng CFX 0 January 29, 2004 12:01
Parallel computation problem in Tascflow dandy CFX 3 April 21, 2002 01:32


All times are GMT -4. The time now is 09:08.