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can anyone please give me detailed answer about the purpose and change of y+ and y*

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Old   May 18, 2016, 03:17
Default can anyone please give me detailed answer about the purpose and change of y+ and y*
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sanjeev kumar.m
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Hi scholars,
please tell me whats the need and purpose of refining the mesh and changing the values of y+ in turbulence flow model.
what is the limits of y+ for general and different problems,and how to calculate the value of y+ for different problems based on flow models.
finally, what is the purpose of Y*

thank you ,
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Old   May 19, 2016, 00:27
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Lucky
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y* and y+ are both inner variables but use slightly different velocity scales for the inner velocity.

Depending on the model, the near-wall turbulence models used need a certain y+ or y*. Hence, your mesh should be fine or coarse enough to meet that criteria. These criteria depend entirely on your models you select (whether explicitly or implicitly).
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Old   May 24, 2016, 06:58
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Y+ is calculated from the shear stress at the wall and can therefor be zero in some cases like stagnation and separation point. That's why there are a y* which is calculated from kinetic energy instead.
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