moving grid in CFX4.4
 

Hi,

I am trying to model the moving grid with USRGRD in CFX4.4. The whole domain (including two blocks and a few patches) is moving. I used IPALL to get the address of all cell vertices and centres in all the blocks and patches. And then specified XC(INODE) as a function of XCOLD(INODE).

I got an error message as flows,

MAXIMUM VOLUME = 0.2319E-11 MINIMUM VOLUME = -.9386E-11

THERE ARE 27 CELLS WHERE THE SIGN OF THE VOLUME CHANGES. THE FIRST 10 HAVE BEEN PRINTED ***> ERROR NUMBER 1 IN FRONTEND PROCESSING

Could you please tell me what can be wrong with my subroutine?

Thank you.

Bing Ma

Re: moving grid in CFX4.4
 

Hi,

It means you are turning some elements inside out. The solver can handle all positive or all negative elements as the sign is just a function of the node numbering, however a mixture of both positive or negative elements means some elements are inside out.

A second explanation is that your node numbering on elements is not consistent.

It's been a long time since I used CFX4 but hopefully these comments are correct.

Glenn Horrocks

Re: moving grid in CFX4.4
 

Hi Glenn,

Thank you for your reply. What you said is quite true. It seems like some of the nodes in an element have been moved, some are not. Therefore the element is inside out.

I used IPALL('*','*','BLOCK','CENTERS'...),IPALL('*','*', 'PATCH','CENTERS'...),IPALL('*','*','BLOCK','VERTI CES'...),IPALL('*','*','PATCH','VERTICES'...) to call the address of every nodes in the domain. Is it possible I can still miss some of the nodes by this way? Could you please tell me how I can get the missing nodes?

Thanks a lot.

Bing Ma

Re: moving grid in CFX4.4
 

You're not quite getting them all.

First, you only need to move the vertices. The centers aren't physical point, but the centroid of the cell.

Secondly, IPALL on the blocks only gets the interior nodes. You're missing the dummy nodes.

Best thing to do is to loop IVERT = 1, NVERT. This will ensure that you hit each and every vertex.

Hope this helps, Jeff

Re: moving grid in CFX4.4
 

Thanks a lot, Jeff, it works.

Bing

Re: moving grid in CFX4.4
 

I am looking for CFX4.4 . Could someone please let me know where I can find it? I will appriciate. Anyother version of CFX if I couldn't find CFX4.4 also will do.

Re: moving grid in CFX4.4
 

Hi Steve,

????

You can get CFX4, 5 and lots of other software from your local ANSYS dealer www.ansys.com - but for some reason I don't think that was the answer you were looking for.

Glenn Horrocks

Re: moving grid in CFX4.4
 

The problem is there is no local dealer in the sh*t place I live. I am not an ansys expert that's why I ordered ansys 9.0 which is the lastest version via a friend of mine and I put him in a lots of trouble for payment on my behalf but when I got ansys 9 I realised CFX is not included in version 9 and now I don't know if I will be able to ask him again for CFX this time.

Re: moving grid in CFX4.4
 

Hi,

If there is no local dealer in your area for ANSYS/CFX then go straight to head office. You can contact them from the details at www.ansys.com

Regards, Glenn Horrocks

Re: moving grid in CFX4.4
 

It is not that easy my friend. A few month ago I purchased a $100 vacuum grease. They sent me grease before recieving payments since I asked for an emergency shipment. I payed them via bank transfer but after a few month still they haven't recived money and I am fighting to find out why money didn't get to them. Untill now there is no one to answer.

Another case is my samsung T200 mobile. It's falt failed and since mobile had warrenty I went to local samsung agent to use warrenty to fix it. They denied and they said it is LCD problem and LCD doesn't have warrenty. I went to court and forced them to fix it and they had to do it but after two month same problem happened again and the same story. Now it is more that one year I am in the court against local samsung agent and couln't succeed in claiming my $30 I paid for flat to get my mobile fixed in a private repair shop.

If I order via ansys.com they will ask for price of the software now or later and I am not sure money will get to them since the only way I can send them money is via bank transfer. In a place bank staff steal your money what you can do.

Thanks for advice anyway. I will try to find a friend in overseas and will ask him to purchase software and bring it to me when he comes back. This seems is the best way of purchasing from overseas for me at the moment.