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Manual DES blending function

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Old   May 25, 2020, 12:54
Default Manual DES blending function
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Jonas
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Hi,


Is it possible to manually specify the DES blending function in parts of the domain whilst also having it calculated according to the normal expression in the rest of the domain?


Many thanks for any input on this !
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Old   May 25, 2020, 15:00
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Not sure if the parameters can be a expression. If so, then you can make them depend on a coordinate using functions like step, max or min. And as such switch them on or off in a certain range of the coordinate....
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Old   May 25, 2020, 15:26
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Hi Gert-Jan,


Thanks for your answer. I'm not quite sure I understand what you mean with 'parameters'? I assume you are referring to the expert parameters? I'm afraid I haven't found anything relating to the DES blending function there.
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Old   May 25, 2020, 17:12
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If you select the DES model in CFX-Pre, you can open the advanced settings tab. There you can change e.g. the BF1 and BF2 values. I thought you mentioned these blend factors that allow you to control the DES simulation......
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Old   May 25, 2020, 19:12
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I wanted to control the blending function directly (not through the SST shielding functionality). Though I must admit that your suggestion is very insightful and inventive, it will only allow me to switch to the very 'safe' F2 shielding functions, given a certain conditional expression is satisfied. Unfortunately, this will not allow me to set the DES blending function - only enable me to control the regions in which an SST blending function is used for shielding. If the solver clips the DES blending function at 1, then this could be bypassed by multiplying the conditional expression for the blending function factor by a large scalar. Thanks for your suggestion.
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Old   May 26, 2020, 03:34
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If you want more control, then you'd better program it yourself or switch to OpenFOAM.
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