It is shown that an eddy diffusion hypothesis suggested by Smagorinsky for use in numerical solutions of turbulent flow problems is consistent with the existence of an inertial subrange at the smallest resolvable scale of the numerical model. The arbitrary constant, assumed by Smagorinsky to be o... Show moreIt is shown that an eddy diffusion hypothesis suggested by Smagorinsky for use in numerical solutions of turbulent flow problems is consistent with the existence of an inertial subrange at the smallest resolvable scale of the numerical model. The arbitrary constant, assumed by Smagorinsky to be of order unity, is shown to be a unique function of the constant of the Kolmogoroff energy spectrum function. An alternative hypothesis, involving an explicit turbulent intensity, is introduced as a possible improvement for flows with large space and time variations of turbulent stress. Show less