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May 14, 2003, 02:52 |
UDS
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#1 |
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Hello to all
I want to solve two coupled equations in the form bellow by UDS but for introducing the time derivative we have three options in Fluent: Default,none and UDF. If I choose Default, both of time derivative will remain. so we have d(fi1)/dt-D.(gama1.D(fi1))=Source1 d(fi2)/dt-D.(gama2.D(fi2))=Source2 If I choose None ,both of time derivative will omit. 0 -D.(gama1.D(fi1))=Source1 0 -D.(gama1.D(fi1))=Source1 In UDF I couldn't do that. So,how do I define this two equations? d(fi1)/dt-D.(gama1.D(fi1))=Source1 0 -D.(gama2.D(fi2))=Source2 Thanks in addvance |
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May 14, 2003, 08:15 |
Re: UDS
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#2 |
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In the UDF DEFINE_UDS_UNSTEADY(name, c, t, i, apu, su) the i is the counter of the UDS's. So with an if statement you can define two different time derivatives for your two UDS's.
More information on fluent 6.1 UDF-manual chapter 4.3.20. |
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May 14, 2003, 08:31 |
Re: UDS
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#3 |
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Thanks for your reply But,If I set apu and su to zero, It takes an error and gives AMG error.
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May 14, 2003, 11:26 |
Re: UDS
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#4 |
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Take for the option time derivative for UDS none and incorporate the time derivative of one UDS in a define_source because the two terms A and B of a source term are equal to su and apu.
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May 15, 2003, 00:33 |
Re: UDS
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#5 |
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Thanks
But,how could I define time derivative. |
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May 15, 2003, 05:45 |
Re: UDS
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#6 |
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The example in the udf manual for DEFINE_UDS_UNSTEADY is nothing more than the time derivative rewritten to use it in that UDF. So you can just copy that.
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May 17, 2003, 05:20 |
Re: UDS
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#7 |
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Thanks again But,If you can please explain about it more. If you have any example please write it down.
sebeci, |
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