Eddy Viscosity in Truncated and Averaged Hydrodynamical Equations

Abstract

An eddy viscosity suitable for use with the spatially averaged Navier-Stokes equation is formulated and compared with Kraichnan's computations of eddy viscosity for use with the truncated spectral equations, in the special case of an energy-constrained inertial spectral range. The formulation is related to Smagorinsky's strain-dependent eddy viscosity. Numerical values of Kolmogorov's constant are established from diverse atmospheric data.