How can we connect our ideas about random convection and relative dispersion of contaminant blobs with this need to model 'smearing ' processes ?
Extrapolations from experiment suggest that the two-dimensional shear layer will consist a t every stage of a linear arrangement of blobs of vorticity.
An example related to the development and coalescence of two initially separated blobs in a cell on a spherical surface is presented.
We now consider the merging of two vortex blobs more quantitatively.
According to table 1 the vortex blobs are initially a bit elongated in the x direction as one would expect.
The shear layer consists at every stage of an array of clusters of vortex blobs.
The size of these clusters, and hence the degree of scatter of the vortex blobs about the midline, determines the layer thickness.
The simple picture of the shear layer as a line of vortex blobs, that merge painvise thus thickening the layer, is not seen.
