error epsilon too small

imanzeydabadi · November 17, 2013, 11:30

Hi
I simulated a cyclone in fluent.now I'm tracking particle in unsteady method.
when fluent go to dpm tracing, print "epsilon too small epsilon too small..."
can any body help me???

pakk · March 6, 2014, 08:09

I just had the same problem.
For me it is in steady-state, laminar flow (so no k-epsilon model used).
I have tried changing the tolerance in the accuracy control of the dpm model, but the same error message keeps coming up.

The solution in my case: I looked at the injection file that I used, and I found out that I made a mistake before, and had given the particles an initial velocity of 1e22 m/s. After fixing that mistake, the particles started with a more realistic velocity, and the "epsilon too small" error disappeared.

GM_XIII · December 13, 2014, 08:15

Hi guys,

I am experiencing the same problem, it is also a laminar flow so I don't really understand what it is referring to epsilon (do someone know?). I reviewed my BCs and nothing seem to be wrong. The particles are accelerated by a volumetric force given by an UDF, maybe this can be the source of the problem, I am testing it. Any hint or idea is welcomed.

Thanks in advance

SJSW · April 8, 2015, 03:10

Hi~
The same error appeared when using DPM and LES.

It said:

"
DPM Iteration ....
epsilon too small
Internal error at line 16140 in file '..\..\src\dpm_path.c' on Node 1.
epsilon too small
Internal error at line 16140 in file '..\..\src\dpm_path.c' on Node 0.
epsilon too small
Internal error at line 16140 in file '..\..\src\dpm_path.c' on Node 1.
epsilon too small
Internal error at line 16140 in file '..\..\src\dpm_path.c' on Node 2.
number tracked = 1, escaped = 0, aborted = 0, trapped = 0, evaporated = 0, incomplete = 0, incomplete_parallel = 0
Parallel particle tracking concurrency: 33%
"

I think that if the error is related to dpm path?
and another question is: what is the meaning of "Parallel particle tracking concurrency: 33%" ?

Can anyone kindly help?
Thank you!

claudy.daniel · September 9, 2015, 13:16

try to increase the turbulent dissipation rate in under-relaxation factor

November 17, 2013, 11:30	error epsilon too small	#1
imanzeydabadi New Member iman Join Date: Nov 2013 Posts: 1 Rep Power: 0	Hi I simulated a cyclone in fluent.now I'm tracking particle in unsteady method. when fluent go to dpm tracing, print "epsilon too small epsilon too small..." can any body help me???

September 9, 2015, 13:16		#5
claudy.daniel New Member Join Date: Sep 2015 Posts: 8 Rep Power: 11	try to increase the turbulent dissipation rate in under-relaxation factor BlnPhoenix likes this.

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March 6, 2014, 08:09		#2
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 27	I just had the same problem. For me it is in steady-state, laminar flow (so no k-epsilon model used). I have tried changing the tolerance in the accuracy control of the dpm model, but the same error message keeps coming up. The solution in my case: I looked at the injection file that I used, and I found out that I made a mistake before, and had given the particles an initial velocity of 1e22 m/s. After fixing that mistake, the particles started with a more realistic velocity, and the "epsilon too small" error disappeared.

December 13, 2014, 08:15		#3
GM_XIII Member David Join Date: Aug 2012 Posts: 48 Rep Power: 14	Hi guys, I am experiencing the same problem, it is also a laminar flow so I don't really understand what it is referring to epsilon (do someone know?). I reviewed my BCs and nothing seem to be wrong. The particles are accelerated by a volumetric force given by an UDF, maybe this can be the source of the problem, I am testing it. Any hint or idea is welcomed. Thanks in advance

April 8, 2015, 03:10		#4
SJSW Senior Member Join Date: Jun 2014 Location: Taiwan Posts: 100 Rep Power: 12	Hi~ The same error appeared when using DPM and LES. It said: " DPM Iteration .... epsilon too small Internal error at line 16140 in file '..\..\src\dpm_path.c' on Node 1. epsilon too small Internal error at line 16140 in file '..\..\src\dpm_path.c' on Node 0. epsilon too small Internal error at line 16140 in file '..\..\src\dpm_path.c' on Node 1. epsilon too small Internal error at line 16140 in file '..\..\src\dpm_path.c' on Node 2. number tracked = 1, escaped = 0, aborted = 0, trapped = 0, evaporated = 0, incomplete = 0, incomplete_parallel = 0 Parallel particle tracking concurrency: 33% " I think that if the error is related to dpm path? and another question is: what is the meaning of "Parallel particle tracking concurrency: 33%" ? Can anyone kindly help? Thank you!