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-   -   Oscillatory flow 101 (https://www.cfd-online.com/Forums/cfx/106222-oscillatory-flow-101-a.html)

Andris August 22, 2012 08:11

Oscillatory flow 101
 
Hi all,
I am using CFX to model oscillatory flow in a bifurcation. BC's are inlet with a velocity defined by a trigonometric expression that I entered, outlet with a relative pressure of 0 and wall with no-slip condition. Initial values are zero for all velocities. Transient flow has been selected, and output control to print results every second.
The mesh is a simple octree mesh.
This is a simple situation but it just simply does not work, I was wondering if I am missing something obvious?
Any help would be greatly appreciated,
Andris

Lance August 22, 2012 08:33

Quote:

Originally Posted by Andris (Post 378170)
it just simply does not work, I was wondering if I am missing something obvious?

besides describing what it is that doesnt work? We cant help you if you dont give us any more info...
error messages? ccl? solver output?

Andris August 22, 2012 09:24

Hi Lance,
here is the error message

An error has occurred in cfx5solve:
writemms exited with non-zero return code 11

I was wondering if this transient problem has to be done in a similar way to as it is done in the tutorials, i.e. taking initial conditions from a steady state domain?

Andris August 22, 2012 09:38

1 Attachment(s)
Here is the geometry I am using,
I readjusted the global initialization to a very small velocity in the y direction,
I get the following error message

ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Floating point exception: Overflow |
| |
| |
| |
| |
| |
+--------------------------------------------------------------------+

+--------------------------------------------------------------------+
| ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Stopped in routine FPX: C_FPX_HANDLER |
| |
| |
| |
| |
| |
+--------------------------------------------------------------------+

Lance August 22, 2012 10:16

http://www.cfd-online.com/Wiki/Ansys...do_about_it.3F

Andris August 22, 2012 10:21

thanks for the link, instead of using an expression, I used an excel file, and got a solution, though the solution was very very bad, I am surprised it worked
I was wondering if this transient problem has to be done in a similar way to as it is done in the tutorials, i.e. taking initial conditions from a steady state domain?


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