Large Eddy Simulation (LES) is based on a separation between large resolved, and small unresolved Sub-Grid Scales (SGS), obtained by applying a low-pass filtering operator on the governing equations. Actually, such filtering operation is often nothing but a formalism while writing the LES equations in continuous form. Indeed, in the so-called
implicit filtering approach
the discretization of both domain and differential operators is practically used as built-in filtering, e.g. see (Sagaut,
). The characteristic filter length Δ is implicitly linked to the computational grid size step
(the only user-defined parameter) by the so-called
sub-filter resolution parameter
. Hence, numerical representation of the filtered variables is associated with a finite number of resolved scales and marginal resolution.