Fluids

Fluids

Y+ value near the wall _ number of BL

    • manelaero2020
      Subscriber

      Hi friends ; 

      I have two questions for you :

      1/ I am simulating airflow around a wing. I have computed Y the height of the first cell near the wall, I found 4 micro m

      I have inserted 6 BL, with a growth rate of 1.1 ( it is impossible to insert more because of the constraint of computation cost)

      Solution converged after 600 iterations, but Y+ was equal to 5, 6, and 7 in the case of some few iterations ( 30 iterations) 

      There was no problem with the rest of the computation.

      Can I worry about the accuracy of the result? Do you think that the problem was an insufficient number of BL or an unsuitable value of Y?   the model of turbulence is spalart allmaras 

      2/ in the case of a turbulent flow, we must resolve viscous and buffer layer Y+ <30. Given that we have computed Y near the wall, how can we choose the right number of BL in the order to resolve Y+<30? 

      Thank you a lot 

      Best regards 

       

    • Keyur Kanade
      Ansys Employee
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