Short- and long-time behavior of eddy-viscosity models

摘要: The short-time behavior of the turbulent viscosity is inferred from immediate response Reynolds stress deduced by Crow [1] for problem isotropic turbulence subjected to a mean strain at time t=0. v defined t → 0 relation T ij =−2vS , where and S rate strain. It follows that v=O(t) 0. Matching short- long-time behaviors, we propose an analytic expression effective valid all time. Using proposed viscosity, K − E model homogeneously sheared reformulate be in both limits. Previously, has been used with form Comparison theoretical predictions results physical numerical experiments presented. Implications large-eddy simulations spectral-space closure theories are discussed.