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Old   February 7, 2003, 17:58
Default CVODE Error message
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Robert
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I am getting an error message in Fluent. I am modeling a dual mode scramjet combustor with hydrocarbon injection. For the Turbulence-Chemistry interaction I am using EDC. The help guide says I should use a segregated solver, but I am using coupled. I am keeping my Courant number low (O -3) and the residual setting lower than default. I know that the CVODE is embedded in the EDC. Every 10 iterations the following error occurs:

CVODE: Limit of 1000 steps reached at t = 2.487e-08s before t-end = 6.7746e-08

With the t values changing. This is a three step reaction with reversable reactions. Any help in solving this would be greatly appreciated. Thanks.
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Old   February 10, 2003, 14:52
Default Re: CVODE Error message
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cg
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For supersonic combustion, the coupled solver is the right choice. To increase the number of CVODE steps (which should get rid of the error message) type this in the text interface...

(rpsetvar 'species/cvode-max-steps 10000)

I think that this variable name is correct: if an error is reported, ask your support engineer for the right name.

Btw, Fluent 6.1 has ISAT which will speed up the chemistry calculations by several orders of magnitude!
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Old   February 12, 2003, 19:28
Default Re: CVODE Error message
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Greg Perkins
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Where is Fluent 6.1 - I thought Fluent were working to a 6-9 month release date?

Hopefully they have fixed the bugs in Fluent 6.0.20 so I don't have to use 5.5 - which is still a good code.

Greg
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