Discussion Groups

Simulation CFD

Reply
Member
cbroer
Posts: 3
Registered: ‎09-19-2012

flow-driven motion => solver error

214 Views, 6 Replies
09-19-2012 07:31 AM

Hi there,

 

I try to run an analysis with flow-driven motion. The object is to rotate a body by airflow. The setup looks like this: One solid volume is surrounded by a rotating region that is surrounded again by a large fluid volume (air). The rotating region is set up as free-spinning with an inertia value. Two BC defined at the surrounding fluid: flow speed and pressure.

 

Actually nothing special so far. But my problem is: After meshing the solver closes unexpectedly. I tried my best with the CFD-help, but could not find the problem.

 

Btw: If defining the rotating region with a "known rotational speed", the analysis runs fine.

Is there any special parameter or trick?

Anyone have ideas?

 

Best Regards,

  Chris

Please use plain text.
Product Support
wildej
Posts: 704
Registered: ‎08-25-2011

Re: flow-driven motion => solver error

09-19-2012 11:12 PM in reply to: cbroer

If you are running CFD2013 try running for 0 iterations first and then run from s(0)



Jon Wilde
Please use plain text.
Member
cbroer
Posts: 3
Registered: ‎09-19-2012

Re: flow-driven motion => solver error

09-20-2012 07:19 AM in reply to: wildej

John,

 

I work with CFD2013. It's the 6th release I gain experience with since CFDesign v9.

 

When running 0 iterations the meshing process runs w/o problems. After that the model appears in the results window for a second or two. The then error "solver closed unexpectedly" pops up. After clicking "OK" at the popup-message, the model switches back to setup mode (pre-processing).

 

That is the way it runs, no matter how may iterations set.

Please use plain text.
Product Support
wildej
Posts: 704
Registered: ‎08-25-2011

Re: flow-driven motion => solver error

09-20-2012 07:36 AM in reply to: cbroer

There is an issue but it should work OK if you run for 0 iterations first, then continue from t(0).

 

I just tested it here and it's OK, this was after replicating your issue if running a number of iterations from 0 (it worked with a known rpm also as you say).

 

Can I confirm that you definitely ran this from 0 for 0 iterations? There should be no error if you do.

Also, what fluid are you using, just air_fixed?

 

Thanks

Jon



Jon Wilde
Please use plain text.
Member
cbroer
Posts: 3
Registered: ‎09-19-2012

Re: flow-driven motion => solver error

09-24-2012 05:21 AM in reply to: wildej

Jon,

 

The model runs now from 0 for 0 iternations. But, tryin to solve any further iteration results in the described solver error.

 

I added a support file of my model. Maybe you could take a quick look.

 

Thanks

  Chris

Please use plain text.
Product Support
wildej
Posts: 704
Registered: ‎08-25-2011

Re: flow-driven motion => solver error

10-01-2012 02:39 AM in reply to: cbroer

You are a paid up subscription customer of ours yes? Just thinking we could move this to a case.



Jon Wilde
Please use plain text.
Product Support
wildej
Posts: 704
Registered: ‎08-25-2011

Re: flow-driven motion => solver error

10-01-2012 03:20 AM in reply to: wildej

Also, I notice that this is compressible. You need to change the inlet conditions. A velocity is unsuitable, try a mass flow rate (this will not change throughout the domain). Also, set a pressure and temp. Is your Total Temperature in the Solve box definitely correct? Take a look at Total T in the help guide.

Also, the domain will likely need to be larger.

 

I suggest you test with an incompressible analysis first



Jon Wilde
Please use plain text.