Hello, I am looking for some help in understanding jet diameter growth due to entrainment. I have an impingement plate positioned approximately 20 cm from the nozzle exit. Is there an equation or information that will allow me to figure out how a free jets diameter grows the further it gets from the nozzle exit. This is so that the rig I have that holds the impingement plate in place does not interfere with the jet growth. Many Thanks Mark.