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Old   December 16, 2011, 13:53
Default Increasing of total temperature
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Roland Rakos
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Hello,

I have a general 3D flow field. It contains a large region (a tube) where strong swirling zone occurs. In this zones the total temperature always becomes larger than the inlet total temperature which was defined as boundary condition. The walls are adiabatic and free slip. I dont understand this. How can the total temperature increase above the inlet total temperature if there is not heat input and friction at the walls. Is this because of the viscosity (internal friction) of material?

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Roland
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Old   December 16, 2011, 16:08
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Glenn Horrocks
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Have you got viscous dissipation turned on? Yes, this could be one explanation.

Also if the simulation is not fully converged you could get this. Also inadequate mesh resolution could contribute.
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Old   December 20, 2011, 12:04
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Is the total temperature locally above the inlet value or is it the massFlowAve(Total Temperature) on a slice plane through the tube? If it's just locally then that's allowed to happen physically. It's similar to a local rise in Total Pressure (see "Rise of Total Pressure in Frictional Flow" - http://adsabs.harvard.edu/abs/1995AIAAJ..33..772I)
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