I have a compressible gas (nitrogen) venting from a pipe. What I am trying to figure out is how fast the gas is exiting the pipe. I know the volumetric flow rate and the area of the pipe, but I cannot use the standard Q=Av formula because that provides me with an exit velocity of Mach 3 (a little extreme). I am assuming compressibility comes into the equation but I don't know how exactly. Any guidance would be great; thank you in advance.