Page History

...

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

...