VORTICITY CONSIDERATIONS AND PLANAR SHEAR LAYERS

Vorticity considerations are employed to experimentally analyze two pl ane shear layers: (i) a small Reynolds number two-stream layer (theta DELTAU/nu = 4.8 x 10(3)) and (ii) a high Reynolds number single-stream shear layer (U0theta/nu = 78 x 10(3)). Statistical properties of the vorticity and velocity fields are presented. The data processing algor ithm permits a spatial correlation function, omega(z)'(tau)omega(z)'(t au + DELTAx)BAR, to be evaluated. A principal finding is that the high Reynolds number correlation function exhibits a quite pronounced dist inction between the ''family'' of large scales (L), 10(-3) less-than-o r-equal-to L/theta less-than-or-equal-to 10, and the small Scales, l/t heta less-than-or-equal-to 10(-3). The sharp distinction in the family of scales is not as pronounced for the small Reynolds number case.