Calculate the dimensionless wall distance (y+) for CFD boundary layer modeling.
Input Parameters
Calculation Results
Enter parameters to calculate
About this calculator
Quick Reference
u*Friction velocity
yNormal distance to the wall
νKinematic viscosity
Overview
y+ is a dimensionless distance from the wall, used in fluid mechanics to define the location in a boundary layer and to determine the appropriate mesh resolution for CFD simulations.
💡
Pro Tips
The formula is y+ = (u* * y) / ν.
u* (Friction Velocity) = sqrt(τ_w / ρ).
For resolving the viscous sublayer directly, you typically need y+ < 1.
For using 'wall functions', y+ is usually between 30 and 300.
!
Fun Facts
"The boundary layer is divided into the viscous sublayer, the buffer layer, and the log-law region, all defined by y+ values."
"Accurate y+ calculation is the first step in setting up any professional-grade CFD simulation for heat transfer or aerodynamics."
"The concept was popularized alongside the 'Law of the Wall'."
