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Old   October 3, 2007, 06:08
Default Zero gradient Temperature Bc
  #1
selim
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Hi all, I need to specify zero static avarage pressure,and zero temprature gradient at the outlet. How can I do this in cfx 11?

Thanks in advance, Selim
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Old   October 3, 2007, 18:32
Default Re: Zero gradient Temperature Bc
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Glenn Horrocks
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Hi,

You cannot specify temperature (or temperature gradient) at an outlet. The temperature at the outlet is defined by the flow upstream only. What are you trying to do?

Glenn Horrocks
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Old   October 4, 2007, 01:56
Default Re: Zero gradient Temperature Bc
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S.
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Can't you specify temperature gradient at the outlet by using the "outlet" boundary condition? Isn't the "outlet" boundary conditions second derivatives equal to 0? So you are indirectly specifying a temperature gradient by choosing the outlet condition.
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Old   October 4, 2007, 18:20
Default Re: Zero gradient Temperature Bc
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Glenn Horrocks
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Hi,

From the CFX V11SP1 theory manual, outlet boundary conditions: "For scalar quantities, the ANSYS CFX-Solver imposes a constant gradient constraint (generally non-zero) at the outlet boundary."

It does not define what gradient it does actually impose or how it is calculated. Does anyone know this?

Regards, Glenn Horrocks
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