vibration at high speed

Dear freinds
I have already designed a perfect laminar jet with cutter.
as through my experiments I found the maximum stable height of laminar jet is a function of nozzle diameter. I am designing of 12mm diameter nozzle and I want that the height be about 4m and 7m horizontal distance.
evry thing is ok but I have two problem.
1-in this speed tha laminar flow start vibrate.
2-the water flow oscilates.
It would be my pleasure if any one suggest his idea.

for me it sounds like you have reach the limit for how long you can make the water travel in laminar flow ?


You say you have the perfect cutter?
Do you mind posting pictures, and info about the hardware.

I have 2 nozzles, a big fountain, 4 huge water tanks, 4 powerful pumps........ but absolutely no working cutter
All my attempts to build a cutter have failed.
So please share info you have


thank you