Hi,

Currently the "PressureOutflow" boundary condition uses the input parameter "P_Inf" to impose the static pressure.
To obtain what you want to achieve you need to define "P_Inf" and set it to the static pressure you want at the outlet.

I hope this helps.

Cheers,
Giacomo

On Sat, Dec 15, 2018 at 8:30 AM 中华腾飞 <592835068@qq.com> wrote:
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!
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