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From these contours, you can observe that the air is being entrained near the jet inlet, and that the jet expands slightly along the x-direction. Also knowing that the flow velocity is related to the stream function Ψ by u = ∂Ψ/∂y and v = - ∂Ψ/∂x, one can see that the stream functions will be smaller in the entrainment and jet stream areas, because the flow is more strongly linear there. 

Now go to 'Plots'-XY Plot and make a plot of how the axial velocity and half-width vary with axial distance x. These can be used to examine the self similarity of the solution. 

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You can see that the axial velocity at the centerline (U_center) decreases sharply after the inlet, and that it will asymptotically approach 0m/s far from the jet. However, the half-width (Y distance at which U=U_center/2) increases along X as the spray expands into the environment. 

To obtain this distance, go to File-Export-Solution Data. Select 'X-coordinate', 'Y-coordinate', and 'Axial Velocity' as values to export. Export them along the centerline, and various X locations (like X=10D) as either an Ascii file to copy into Excel, or as a CFD-Post file. Plotting Y-coordinate approximate locations at which U=U_center/2 gives the half width variation:

An additional step is to plot the self-similar profiles U/U_center at various X locations, using the same exported data. The profiles appear to be self similar, although at X values closer to the inlet they will not match exactly due to the additional entrainment effects.

Go to Step 4: Turbulent Jet Setup and Solution

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