[Hicha04m]

Hi,

i simulate fluid with particle and use User routine to calculate the drag coefficient but i get 0


Particle Diagnostics
================================================== ====================

+--------------------------------------------------------------------+
| Particle Fate Diagnostics |
+--------------------------------------------------------------------+
| Particle type | Fate type Particles |
+--------------------------------------------------------------------+
| Particle | Entered domain : 1000 |
| | Left domain : 1000 |
+--------------------------------------------------------------------+

+--------------------------------------------------------------------+
| Particle Equation | Total source and source change rates |
+--------------------------------------------------------------------+
| | Equation Source Rate |
+--------------------------------------------------------------------+
| Domain: Default Domain |
+--------------------------------------------------------------------+
| Particle | x-Mom 0.000E+00 0.0000 |
| | y-Mom 0.000E+00 0.0000 |
| | z-Mom 0.000E+00 0.0000 |
+--------------------------------------------------------------------+

[ghorrocks]

Have a think about what the message is saying. It is saying it generated 1000 particles and 1000 particles left the domain. The source term bit states none of these particles interacted with the flow.

So I suspect some combination of:
* You seeded the particles outside the domain
* You seeded the particles on a boundary which was flowing out
* Your particle time step was so large that they wizzed right across the domain in one time steps.
* Or something else where the particles do not interact with the domain.

[Hicha04m]

Thank you for your answer. I get now this message


Parallel run: Received message from slave
-----------------------------------------
Slave partition : 3
Slave routine : ErrAction
Master location : RCVBUF,MSGTAG=1032
Message label : 001100279
Message follows below - :

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

Parallel run: Received message from slave
-----------------------------------------
Slave partition : 3
Slave routine : ErrAction
Master location : RCVBUF,MSGTAG=1032
Message label : 001100279
Message follows below - :

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

+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| The ANSYS CFX solver exited with return code 1. No results file |
| has been created. |
+--------------------------------------------------------------------+

End of solution stage.

[ghorrocks]

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

[Steffen595]

in other words, you get 0 because it did not run the calc in the 1st place