1. o ^ " " " T J ^
2. NACA T M 726, 1933. their energy from the mean motion of the shear flow whose overall dimensions determine their scale or, in the case of grid-generated turbulence, their scale is determined by t h e mesh size. T h e large eddies loose their energy to small eddies which in t u r n pass it on to still smaller eddies. T h e smallest eddies dissipate most of the energy by direct action of viscosity. Any directional effect of the shear flow gets progressively less as we go from large to small eddies; the latter are isotropic.