### 4.2.6. Solver Yplus and Yplus

Yplus (y +) is the dimensionless distance from the wall. It is used to check the location of the first node away from a wall. This was more important when standard wall functions were used, as you had to avoid y + values smaller than approximately 20. With the scalable wall functions and the automatic wall treatment, these values are only provided for information on the near wall resolution. Two variables related to y + are output to the results file, Yplus and Solver Yplus.

- The variable `Yplus` is based on the distance from the wall to the first node and the wall shear stress. This is the usual definition in the CFD community.

- The variable `Solver Yplus` is used internally by the CFX-Solver. It uses different definitions for the wall distance of the first wall point. This variable is available for backwards consistency, but is of little use to you.

There is usually no need for you to work with the y + used internally (`Solver Yplus`). The information required to judge the near wall mesh spacing should be based on the standard y + (`Yplus`) definition.

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