The Y+ Calculator app is a handy tool for calculating the grid spacing to achieve a target y+ value for viscous computational fluid dynamics (CFD) computations. Simply specify the flow conditions, the desired y+ value, and compute your grid spacing.
If you are an engineer running viscous CFD computations, setting the distance of the first grid point off the wall is essential for accurately resolving the boundary layer. Y+ is a non-dimensional measure of wall spacing that has been normalized by wall shear stress. For turbulent boundary layers, y+ should be 1.
The Y+ Calculator computes the height of the first mesh cell given a target y+ value and the flow conditions. The app works in either SI or Imperial units and quickly resets to sea-level conditions. Its computations are based on flat-plate boundary layer theory from Frank M. White’s Fluid Mechanics 5th edition, page 467.
The Y+ Calculator is available for both iOS and Android so download your preferred version today. For more information see the Y+ Calculator page on our website.
Update: It’s worth noting that the app is free.