Hi all! I have met some problems in using compressible flow solver. When i begin to calculate ,after some steps ,it will stop and print an error on the screen called'vacuum is generated by given data'. Now, i will talk about my task. If you open the fight.geo with gmsh 3.0.6,you will see a box. You can also open the fight.msh file with gmsh which you can see the generated meshes .Inlet is on the left and outlet is on the right. I want to give total values like total temperature and total pressure on the inlet (T*=1600K,P*=1312800Pa,Ma=0.33),but when i see the tutorials about compressible flow solver,it seems that i should give values like rhoInf ,rhoInf*uInf and so on,i don't know whether my understanding is right or not .I have to calculate static values through total values and i do that .You can see my fight.xml file,the REF=0 is the boundary of inlet,and values use the parameters defined before.Then i want to give static pressure on the outlet, on the REF=1, i use the 'pressureoutflow' condition,because of no examples of this condition, i don't know how to set right values.... On the REF=2, i want to use 'walladiabatic' condition ,because of no examples of this condtion,i also don't know how to set right values... Initial condition is same to the inlet. I hope you can give me some suggestions. Looking forward to your reply!