Jet mixing: the role of numerical flow visualization

Entrainment can be defined as the thickening of a shear layer in the streamwise direction due to an increase in the volume occupied by the vorticity-containing fluid. The extent to which this process occurs depends heavily upon the geometry of the shear layer, with an elliptical jet, for example, exhibiting much greater entrainment than a circular one. It was desired to characterize the entrainment process and to explore the means by which the entrainment might be further enhanced by using the tool of numerical flow visualization to explore the results of numerical simulations and linear stability analysis.

Because the results of preliminary numerical flow simulations were so topologically complex, linear stability analysis (LSA) was employed to generate simpler flows. These results provided important insight into the early stages of the (near field) mixing process and provided a means for testing the accuracy of the visualization tool.