CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > ANSYS Meshing & Geometry

Match Control and Symmetry Boundary Condtions in a quasi 2D calculation

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

LinkBack Thread Tools Search this Thread Display Modes
Old   May 15, 2012, 09:53
Default Match Control and Symmetry Boundary Condtions in a quasi 2D calculation
New Member
Join Date: Mar 2012
Posts: 27
Rep Power: 12
peterputer is on a distinguished road
i ve a question regarding "Match Control" in Workbench Meshing. For illustration issues i attached a screenshot of my geometry. It represents a fluid slice of 0.5° in circumferential direction with an inflow at the bottom, a cavity, a throat section and an outflow at the top.
As boundary conditions, i set walls, inlet and opening at the faces in circumferential direction and an interface with fluid fluid 1:1 connection at the faces normal to circumferential direction.
In the Ansys WB meshing tool, l i set "match control" for faces with fluid fluid interface, so that i get a 1:1 matching mesh in circumferential direction. Settings for "match control" are "transformation: Cyclic", "axis of rotation: global coordinate system".
If i run the solver with these settings i get an error msg. If i dont use "match control" for these faces the calculation runs w/o any problem.
I dont get the problem, since the mesh should be better for the solver if i add "match control", so i force it to be a 1:1 sweep in circumferential direction.
If you look closely at the two pictures attached, left one shows boundary conditions for the case w/o "match control", right one shows boundary conditions with "match control".
For the second case the solver seems to ve problems with the interface boundary condition.
So if anyone could explain me that behavior.

| ERROR #002100048 has occurred in subroutine SU_BNEXT. |
| Message: |
| All vertices for a fluid domain lie on boundaries. This is |
| considered to be a fatal error because control volume gradients |
| cannot be calculated, leading to serious discretization error. |
| |
| A common cause for this error is a mesh which is only one |
| element thick, without symmetry or 1:1 periodicity on the lateral |
| boundaries. If you have this situation, and the domain is |
| two-dimensional, please change the lateral boundary conditions |
| to symmetry or 1:1 periodicity. Alternatively, for |
| three-dimensional simulations, please ensure that your mesh |
| has at least two elements across. |
| |
| Execution is terminating. This error message can be bypassed by |
| setting the expert parameter 'boundary vertex check = f', but |
| be aware that doing so may lead to sigificant solution error.
Attached Images
File Type: jpg Fluid Flow CFX.jpg (27.4 KB, 44 views)
File Type: jpg Fluid Flow CFX_match.jpg (29.9 KB, 39 views)
File Type: jpg match_control.jpg (17.7 KB, 35 views)
peterputer is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
SST in 2D? Jesper Sørensen CFX 16 December 23, 2006 09:40
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 16:55
New topic on same subject - Flow around race car Tudor Miron CFX 15 April 2, 2004 07:18

All times are GMT -4. The time now is 02:52.