Is it necessary to make a guide nozzle for a water engine?

I was wondering, why do some engines have a guide nozzle? Does it somehow affect the strength of the water jet and its density? I decided to try to answer this question using a simulator in Blender and the FlipFluids addon.

[@YG-oy1fp]

Amazing😊

[@dagazstudio2105]

Nice😮

[@Matt-mh3ol]

So.. no?

[@KabanKabanus]

I also think that there is almost no difference left

[@Stories_from_Ai_world]

где уроки? давай уроки

[@KabanKabanus]

Уроки пока не успеваю делать :(