Oscillatory flow 101

Andris · August 22, 2012, 08:11

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

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

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?

August 22, 2012, 08:11	Oscillatory flow 101	#1
Andris Member Join Date: Aug 2012 Posts: 35 Rep Power: 13	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

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August 22, 2012, 09:24		#3
Andris Member Join Date: Aug 2012 Posts: 35 Rep Power: 13	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?

August 22, 2012, 10:16		#5
Lance Senior Member Lance Join Date: Mar 2009 Posts: 669 Rep Power: 22	http://www.cfd-online.com/Wiki/Ansys...do_about_it.3F

August 22, 2012, 10:21		#6
Andris Member Join Date: Aug 2012 Posts: 35 Rep Power: 13	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?