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From the converged solution, plot the stream function as you did in the previous section:

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. 

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To make the plot of the velocity variation along the centerline, adjust the XY plot dialogue box (in particular, adjust the plot direction to be along X):

This will give you the centerline plot:

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. 

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