Estimating Y+

Rahul_P1
Rahul_P1
Altair Employee
edited October 2020 in Community Q&A

What is the length scale, coefficient, power in the Y+ Estimator. What are required values ? How to find the Y+ ?
please see the attached screenshot
sw891-SS-5.JPG

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Answers

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited February 2015

    The screenshot you are showing represents a user defined relationship for estimating the y+ in AcuConsole. If you click on the 'Whats this' icon in the main toolbar, then click on the 'Power' entry in the panel, it will show the equation that is used to determine the Y+ for this use case:

    Y+ = (Y1/coeff *Len) * Re^power

    Y1 = first layer height
    coeff = Coefficient
    Len = Length Scale
    power = Power

    The Reynolds Number is estimated based on the material properties supplied by 'Material model' and the length and velocity scales.

    Note that the 'Estimated Y+ method'=User is typically only used if you are working with an application for which the 'Flat Plate' and 'Pipe' relations don't work well, and you know the proper scaling. In my experience, the predefined approaches are pretty good for most applications. I use 'Pipe' for internal flows and 'Flat Plate' for external flows.
    Attached Thumbnails
    Y+Estimator.png

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