the flow is compressible and inviscid. i have the inlet pressure value and outlet velocity . is it correct to give velocity at the exit of the flow for a compressible condition. fluent gives a warning message for this case. kindly pls help in this.

Hi,

is ur flow subsonic or supersonic. depending on the type of flow u will decide the boundary conditions and we look at characteristics to define the boundary conditions. for subsonic flow of the three characteristics two will go into the domain and one will come out at the inlet and out let so u should specify two conditions out of three(density, pressure, velocity). so if u specify two the third one will be extrapolate at the inlet as well as outlet. in supersonic flow u should all the three characteristics will enter into the domain at inlet and leave at the exit so no boundary conditions will be specified at the exit all the values are extrapolated and u should specify the all the boundary conditions at the inlet.

this is the basic theory so extract the information and use accordingly

sir thank u so much for explaining this. i have gone thru the theory in Compresssible Flow by Anderson. but i was not sure how to give bcs in fluent. now i got idea abt it. thank u so much sir.

i have one more doubt abt using the FLUX TYPE solvers for this case.( shock capturing related).. whether to use AUSM or Roe solver.

when using AUSM solver i found that solution is not converging it is repeating. pls help

Hi Sorry, I dont have much Idea on shock related issues(meaning computationally) I did not try as of now, but CFD by chung you have an algorithm or a scheme relating shock capturing mechanism. I know how the things work numerically in shock a little bit.

I would like to study the nozzle analysis in FLUENT.