The first LES model to be created was the Smagorinsky one. The basic problem is the estimation of the turbulent viscosity : Viscosity_turb = [ Coef . Delta ]^2 * |S| |S| : magnitude of the strain-rate tensor Coef : Smagorinsky coef Delta : Filter width And here starts the problems : Coef is constant in this model, but in real life, it depends on the flow and is actually different everywhere in the domain, so a bad estimation of this value (it is bad anyway, since OF will assume it's the same in the whole domain) can lead to unproper results. Close to the wall, the viscosity should tend to 0, and it is not true with the given formula, so a damping function is applied (vanDriest), to reduce the value of the viscosity close to the wall. The damping is applied up to y+ = 500. Main disadvantages of the Smagorinsky model: - Too dissipative in laminar regions - Not good for laminar-turbulent transition (due to the constant Coef I guess) - Backstatter is not modeled (sometimes, smaller eddies are actually giving energy to bigger eddies)