Prism / Inflation Layer Mesh Calculator

Calculate total inflation-layer thickness, last-layer height, and target boundary layer coverage for near-wall CFD meshes.

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Determining the total thickness of the prism/inflation layer is critical for capturing the boundary layer accurately in CFD simulations. Use this calculator to compute the total thickness and last layer height of your near-wall mesh based on the first cell height, growth rate, and number of layers.

Governing Formula

hi=y1⋅ri−1h_i = y_1 \cdot r^{i-1}
T=y1rn−1r−1(r≠1)T = y_1 \frac{r^n - 1}{r - 1} \quad (r \neq 1)
T=n⋅y1(r=1)T = n \cdot y_1 \quad (r = 1)
m

Height of the cell adjacent to the wall.

dimensionless

Ratio of consecutive layer heights (must be > 1). Typically 1.1 - 1.3.

integer

Total number of inflation layers (must be ≥ 1).

m

(Optional) Used to calculate coverage percentage.

Total Thickness

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Awaiting Input

Verify thickness against your CFD solver setup, mesh generator settings, and boundary layer estimates.

Assumptions & limitations

Limitations

  • Geometric Series: This calculator assumes a perfect geometric progression. Some mesh generators use different spacing laws (e.g. smooth transition) which may yield slightly different total thicknesses.
  • No Inverse Mode Yet: Note that solving for growth rate (inverse mode) is not supported in this version.
  • Manual Inputs: Inputs must be provided manually; they are not auto-pulled from the y+ or boundary layer calculators at this time.

Related Resources

y+ First Cell Height Calculator →Boundary Layer Thickness Calculator →View all Engineering Calculators →