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Old   July 26, 2005, 09:32
Default Turbulence Models
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Meri
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I need some help or explanations to resolve some issues regarding turblulent modeling in CFX, I am studying an external flow problem and comparing with wind tunnel test. I have tried different schemes in the program : The SST-with high resolution is pretty correct predicting the Lift. K-epsilon with Upwind provides (although still off)the closest to the Drag and The SST with specified blend is in between. I will like to know if anyone knows how the Torque is being calculated in the program, secondly I wonder if the High resolution can be improved. Perhaps some one has some experience with this. Thanks.
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Old   July 26, 2005, 18:31
Default Re: Turbulence Models
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Glenn Horrocks
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Hi,

You might get better accuracy using the specified blend factor spacial differencing rather than high resolution. Use a blend factor of 1.0 to use purely second order differencing. This may give an increase in accuracy over high-resolution differencing.

The torque reported in the output file is around the default coordinate system, that is the point 0,0,0 in your mesh model.

Regards, Glenn Horrocks
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Old   July 27, 2005, 01:49
Default Re: Turbulence Models
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Meri
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Thanks Glenn, Suppose I desire the Torque about a different location, like the centroid of my object in the domain ? I am gradually adjusting the blend factor to see its influence.
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Old   July 27, 2005, 03:40
Default Re: Turbulence Models
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Johnson
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Hi,

In CFX-Post you can use the Function Calculator to evaluate the torque on any locator about any global axis, and also about any user Coord Frame axis created in CFX-Post.

Regards,

Johnson
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