well,nThanks a lot Mr Array ,nI am trying to design a nozzle this nozzle is fed by a pump with 60 m3/s and an input pressure of 10 bars ( for me it is not logic but I am stick with my thesis supervisor idea).nThis nozzle will be used to provide air excitation to a beam for the purpose of vibration calculation. the beam is excited with a pressure of 2-3 bars.nSo what I am thinking is to design a nozzle with this principle P2/P1 = A2/A1 = D2/D1 ( A = area , P = Pressure, D= Diameters) .nTo have a better excitation I need to provide 2-3 bars of dynamic pressure and the flow need to be laminar so I will have that an equal air distribution at the point where I will be applying this pressure on the beam so like applying a force in a single point. nif I am correct in the explained approach so which viscous model should I apply during simulation? the boundary would be an inlet of 10 bars ( input diameter was 10 mm and outlet is 2 mm),nhow to know if I have a laminar or a turbulent flow since I do not have velocity? from the given data.n nthanks a lot for your feedbacksn