Here is the graphic for a diverging nozzle.
If you look at the lower half,you'll see a notchback roofline with separated flow following the 'template' at the 'top'.
If the inner walls of the nozzle are more a K-form (Koenig-Fachsenfeld/Kamm),there'll be re-attached flow on the 'boot.'
In a perfume sprayer/carburetor,the 'template' is swung,360-degrees inside the inner wall of each barrel to create the venturi which creates the Daniel Bournoulli low pressure which will lift the perfume,gasoline through the metering jet from the bowl
