On the use of relaxation methods for localized dynamic models

An analogy with the use of relaxation methods is identified in both the Lag rangian dynamic model [J. Fluid Mech. 319, 353 (1996)] and the localized dy namic model [Phys. Fluids 7, 839 (1995)]. A general way to introduce a rela xation method for dynamic models is proposed, together with the ability of deriving constants without using Germano's identity [Phys. Fluids A 3, 1760 (1991)]. The resulting family of models contains a relaxation parameter r( a) and leads to a strictly local and stable modeling, as shown by a posteri ori tests in channel flow for Re-tau=180. The influence of r(a) is briefly discussed. (C) 2000 American Institute of Physics. [S1070-6631(00)51312-9].