The description of turbulent flows is based on the assumption that instantaneous flow variables satisfy the Navier-Stokes equations. This assumption seems to be well supported, as “Direct Simulations” of simple, low-Reynolds number turbulent flows have been successful (see Orszag and Israeli, 1974; Orszag, 1978 and Rogallo, 1982). Most researchers in the turbulence field accept the aforementioned assumption as an axiom and use it as the basis for the development of statistical theories or models for numerical simulation. Moulden et al. (1978) analyze the applicability of continuum concepts to the description of turbulence and conclude that if the Newtonian constitutive relation is valid, then it is plausible to accept that turbulent flows instantaneously satisfy the same dynamical equations as laminar flows.
KeywordsCoherence Vorticity Convolution Advection Geophysics
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