Issue with Mesh Statistics
 

Hi All

I am doing a Rotor- Stator Simulation with CFX. It is a Quasi2D Simulation.

I tried to do the simulation with different Z direction Extrusion (thickness). And all the time it was one cell thikness (Z = 1mm, 2.5mm, 5mm) just to know the effects of extrusion in the results.

But with respect to the MEsh statistics the values are changing which was pretty expected

For 1 mm

+--------------------------------------------------------------------+
| Mesh Statistics |
+--------------------------------------------------------------------+
| Domain Name | Orthog. Angle | Exp. Factor | Aspect Ratio |
+----------------------+---------------+--------------+--------------+
| | Minimum [deg] | Maximum | Maximum |
+----------------------+---------------+--------------+--------------+
| Rotor | 35.9 ok | 56 ! | 64 OK |
| Stator | 36.3 ok | 33 ! | 669 OK |
| Global | 35.9 ok | 56 ! | 669 OK |
+----------------------+---------------+--------------+--------------+
| | %! %ok %OK | %! %ok %OK | %! %ok %OK |
+----------------------+---------------+--------------+--------------+
| Rotor | 0 2 98 | <1 <1 100 | 0 0 100 |
| Stator | 0 <1 100 | <1 <1 100 | 0 0 100 |
| Global | 0 1 99 | <1 <1 100 | 0 0 100 |
+----------------------+---------------+--------------+--------------+


For 2.5mm

+--------------------------------------------------------------------+
| Mesh Statistics |
+--------------------------------------------------------------------+
| Domain Name | Orthog. Angle | Exp. Factor | Aspect Ratio |
+----------------------+---------------+--------------+--------------+
| | Minimum [deg] | Maximum | Maximum |
+----------------------+---------------+--------------+--------------+
| Rotor | 43.1 ok | 17 ok | 161 OK |
| Stator | 34.9 ok | 34 ! | 661 OK |
| Global | 34.9 ok | 34 ! | 661 OK |
+----------------------+---------------+--------------+--------------+
| | %! %ok %OK | %! %ok %OK | %! %ok %OK |
+----------------------+---------------+--------------+--------------+
| Rotor | 0 2 98 | 0 <1 100 | 0 0 100 |
| Stator | 0 1 99 | <1 <1 100 | 0 0 100 |
| Global | 0 2 98 | <1 <1 100 | 0 0 100 |
+----------------------+---------------+--------------+--------------+

For 5mm
+--------------------------------------------------------------------+
| Mesh Statistics |
+--------------------------------------------------------------------+
| Domain Name | Orthog. Angle | Exp. Factor | Aspect Ratio |
+----------------------+---------------+--------------+--------------+
| | Minimum [deg] | Maximum | Maximum |
+----------------------+---------------+--------------+--------------+
| Rotor | 41.2 ok | 17 ok | 321 OK |
| Stator | 34.4 ok | 34 ! | 661 OK |
| Global | 34.4 ok | 34 ! | 661 OK |
+----------------------+---------------+--------------+--------------+
| | %! %ok %OK | %! %ok %OK | %! %ok %OK |
+----------------------+---------------+--------------+--------------+
| Rotor | 0 2 98 | 0 <1 100 | 0 0 100 |
| Stator | 0 1 99 | <1 <1 100 | 0 0 100 |
| Global | 0 2 98 | <1 <1 100 | 0 0 100 |
+----------------------+---------------+--------------+--------------+


So now my doubt is what exactly is this expansion factor and how is it controlled ? Is it ok to have these values and still run the simulation ? I am running it in Double Precision. If you see the Aspect Ratio value its going high and they mention it as OK. Normally the Aspect ratio has to be 1 right ?

Kindly correct me if I am wrong. !!

If it converges and the results are accurate then it is fine.