Y+ Wall Spacing Calculator
Accurate First Cell Height (Δy) is crucial for capturing boundary layer physics. This tool helps you size your prism layers for CFD simulations based on your desired Y+.
Flow Parameters
Input
m/s
m
kg/m³
Pa·s
Mesh Strategy
TargetsMesh Dimensions
ResultFirst Cell Height (Δy)
— m
Re: —
Est. Boundary Layer (δ)
— m
Enter flow parameters
Formulas Explained
First Cell Height (Δy)
Δy = 2 × (y+ μ) / (u* ρ)
Calculated for cell centroid at Y+.Reynolds Number (Re)
Re = (ρ × U × L) / μ
Determines flow regime (Laminar/Turbulent).Friction Velocity (u*)
u* = √(τw / ρ)
Based on wall shear stress.Skin Friction (Cf)
Est. using Schlichting (External) or Blasius (Internal) correlations.