An evaluation of a conservative fourth order dns code in turbulent channel flow

Direct numerical simulation (DNS) and large eddy simulation (LES) of turbulent flows require a numerical method that is able to capture a wide range of turbulent length scales. In DNS, all the turbulent length and time scales are resolved. In LES, the large energy carrying length scales of turbulence are resolved and the small structures are modeled. The separation of large and small scales is done using a ltering procedure that is applied to the Navier-Stokes equations. The eect of the small scale turbulence on the resolved scales is modeled using a subgrid scale (SGS) model. Widely used SGS models are the scale similarity models by Bardina et al. (1980) and Liu et al. (1994) and the eddy viscosity based dynamic Smagorinsky model proposed by Germano et al. (1991). In general, scale similarity models do not dissipate enough energy, and eddy viscosity models do not carry enough stress (Baggett et al. (1997) and Jimenez (1998)). SGS models tend to over- and underpredict velocity fluctuations (Kravchenko & Moin (1997), Domaradzki & Loh (1999), Sarghini et al. (1999)). SGS models typically use information from the smallest resolved length scales to model the stresses of the unresolved scales. Therefore, it is of great importance that these re