Skip to content
cfd-lab:~/en/tools/grid-convergence-indexonline
$ cd ..

Grid Convergence Index

Compute observed order, Richardson extrapolation, and GCI from three-grid solutions.

visual calculatorNumerics & Stability

Read the flow shape before trusting the number.

This page turns a CFD setup into regime, scale, and dominant-effect cues. Adjust the calculator below and compare the moving graphic with the computed result.

01
input scale
02
model
03
check
verificationGCIRichardson extrapolationmesh convergence
formula
KaTeX rendered
GCI_21 = F_s |(phi1 - phi2)/phi1| / (r_21ˆp - 1)\begin{aligned}\text{GCI\_21 = F\_s |(phi1 - phi2)/phi1| / (r\_21\^{}p - 1)}\end{aligned}
ASCII sourceGCI_21 = F_s |(phi1 - phi2)/phi1| / (r_21^p - 1)
observed p
1.2224
extrapolated phi
0.9750
GCI_21 (%)
5.5147
asymptotic ratio
0.1945

Assumes monotonic three-grid convergence. Treat non-monotonic values as a warning, not a certification.