https://forums.autodesk.com/t5/cfd-forum/venturitube-inside-a-box/m-p/5887786#M20668 The Mach number will go above 0,8.<BR /><BR />"If the device is fed from a pressurized holding tank, and the outlet pressure is known" - thats the case thus i have to add inlet pressure and outlet pressure. Where is the mistake? Sun, 01 Nov 2015 23:21:20 GMT Anonymous 2015-11-01T23:21:20Z