If we have an air flow in a tube that had d=0.5m however the diameter of the air flow on the inlet side is only 0.2m with a velocity of 0.13m/s. By simulating it through fluent we observe the occurrence of two regions one laminaire and the other is turbulent. The problem is that this observation is against what Reynolds states since for such a velocity and diameter we tend to have Re=1800 witch means just laminar region can u explain why did the turbulence occurred?