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LES Resolution Planner

Compare grid spacing, Kolmogorov scale, and Smagorinsky SGS viscosity to visualize LES/DNS feasibility.

visual calculatorTurbulence & Wall Modeling

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
LESDNSSmagorinskyKolmogorovmesh
formula
KaTeX rendered
Delta = (dx dy dz)ˆ(1/3)eta = (nuˆ3/epsilon)ˆ(1/4)nu_sgs = (Cs Delta)ˆ2 |S|\begin{aligned}\text{Delta = (dx dy dz)\^{}(1/3)}\\[0.35em]\text{eta = (nu\^{}3/epsilon)\^{}(1/4)}\\[0.35em]\text{nu\_sgs = (Cs Delta)\^{}2 |S|}\end{aligned}
ASCII sourceDelta = (dx dy dz)^(1/3), eta = (nu^3/epsilon)^(1/4), nu_sgs = (Cs Delta)^2 |S|
LES resolution mapfilter width: (dx dy dz)^(1/3)etaDeltaresolved eddiesSGS modelLarge structures stay on the grid. Motions smaller than Delta move into the SGS model.Delta/eta = 4.10, nu_t/nu = 0.58
Delta (m)
0.0016
eta (m)
0.0004
Delta / eta
4.10
nu_sgs / nu
0.58
nu_sgs (m^2/s)
8.739e-6
tau_eta (s)
0.0100
u_eta (m/s)
0.0387
verdict
wall-resolved LES candidate

The geometric filter uses Delta = (dx dy dz)^(1/3). The max-spacing option is more conservative for stretched cells. Treat this as a planning sanity check, not a replacement for spectra, resolved kinetic energy, or grid-convergence evidence.

LESDNSSmagorinskyKolmogorovmesh