SYMPTOM:
When using MFR interfaces of type 'frozen rotor', 'stage' or 'transient rotor stator' and the direct intersection algorithm obtained using the expert parameter setting 'ggi intersection algorithm =2' , there is the possibility for the flow solver to rule out faces which are possibly not degenerate, i.e. should be intersected but are not. This would lead there to be non-overlap regions on the interface where there should not be. An error message like the following may be obtained:
+--------------------------------------------------------------------+
| ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Floating point exception: Divide by zero |
| |
| |
| |
| |
| |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| Writing crash recovery file |
+--------------------------------------------------------------------+
Details of error:-
----------------
Error detected by routine PEEKR
CDANAM = RTIME_DTEND
CRESLT = NONE
Current Directory : /FLOW/SOLUTION/TSTEP0/CLOOP0/ZN1
PROBLEM:
The problem is in the detection algorithm for degenerate faces. This algorithm should be comparing the physical (x,y,z) face edge lengths with an element volume length scale, whereas the code currently compares the normalized face edge lengths in cylindrical coordinates (eta,theta) to a physical based element volume length scale.
|
WORKAROUND: Use the default pixel intersection algorithm, possibly with the expert parameter 'ggi edge scale factor' increased to 1.0E-3. FIXED IN: ANSYS CFX Release 11.0 Service Pack 1. Note that even with this fix, it may still be necessary to increase the value given to the expert parameter 'ggi edge scale factor'. |
||
|