# Turbulence

In wind tunnel experiments, most flows occur at Reynolds numbers above $10^{5}$, hence most wind tunnel simulations are turbulent. 
Since the smallest turbulence scales cannot be captured, it is more common to perform large eddy simulations (LES), in which the flow large scales are explicitly solved and the small are modeled:

```{figure} /_static/img/user_guide/02_config/energy_curve.png
:alt: Energy curve
:align: center

Energy curve
```

We usually adopt the Smagorinsky subgrid model with constant of 0.17, which is set in the `models.LES`:

```yaml
    models:
      LES:
        model: Smagorinsky
        sgs_cte: 0.17
```

In LES simulations it is possible to export the macroscopic `omega_LES` which can be used to find the subgrid viscosity $\nu_{\mathrm{SGS}}$.