Hi, I'm a final year master's student doing a study on relief valve tailpipe design for my final year project. The system which the relief valve is fitted to is a high pressure breathing air gas cylinder (300 bar) on board a large ship and it vents to atmosphere via piping which can be between 30 and 100 metres long and include bends and changes in section. I am looking for any advice on how to go about this study... From what I have read etc so far I think that when overpressure occurs and the relief valve opens the gas will flow through the tailpipe and increase in velocity until the flow is choked. This choked flow will create large resultant forces against the inner walls of the piping and it is the magnitude of this force that I should be trying to work out in order to determine pipe diameters/mountings requirements etc. Does this sound like I am along the correct tracks? Also I am working under the assumption that the gas involved is compressible and unsteady and therefore I will have to use isothermal gas laws rather than bernoullis? Any suggestions on literature/resources etc would be gratefully appreciated since I am a little lost with this project so far! Cheers.