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-   -   Divergence problem for species transport model (http://www.cfd-online.com/Forums/fluent/47322-divergence-problem-species-transport-model.html)

MY February 14, 2008 01:33

Divergence problem for species transport model
 
Hello all,

I'm solving a species transport model with wall surface reaction on parallel FLUENT. The surface reaction UDF is compiled fine and UDF library is loaded, but when calculation starts I get the following error:

divergence detected in AMG solver: species-0

divergence detected in AMG solver: species-0

divergence detected in AMG solver: species-0

divergence detected in AMG solver: species-0

divergence detected in AMG solver: species-0

divergence detected in AMG solver: species-0

Primitive Error at Node 0: floating point exception

Primitive Error at Node 1: floating point exception

Primitive Error at Node 3: floating point exception

Primitive Error at Node 4: floating point exception

Primitive Error at Node 2: floating point exception

Primitive Error at Node 5: floating point exception

Error: floating point exception

Error Object: #f

after about three iterations. The UDF defines a wall surface reaction rate for laminar finite-rate model and does not involve any calculation that requires sending or receiving data from another compute node (or the host) and therefore the code is not parallelised.

Can anyone guide me as to what might be the cause of this error?

Many thanks in advance

Soulstealer April 7, 2012 09:01

How to set boundary conditions
 
Hi,
I am a beginner in fluent and find it difficult to set up boundary conditions.
Can someone please help how to setup boundary conditions.I am given two options 1.interior-solid 2.wall-solid.
My project is to estimate the energy losses in an open channel bend.
Thank You for your response

Bigunclejethro July 10, 2012 09:18

Hi MY - from what I've read the floating point error occurs as a result of an impossible mathematical operation (ex - dividing by zero). I have yet to find out exactly how this happens but possible solutions include reducing your timestep (transient flow), reducing the courant number (coupled solver). These have worked for some people but have not worked for me. Maybe you will have better luck.

Soulstealer - you need to define the boundary names before going into fluent. This can be done in the Ansys Mesher by clicking on the face, right click and select named selection. Once this is done, FLUENT will show these boundaries in the Boundary Conditions panel and allow you to set them up

tppraj January 11, 2014 05:46

Species with boundary condition
 
Hai friends,
I am new in fluent. I don't know how the species is introduced in the fluent for the nozzle flow. I am using the density based implicit solver with structured mesh. so please help me to introduce the species in the fluent.
Thanking you


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