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-   -   compressible flow solver in OF1.6 (https://www.cfd-online.com/Forums/openfoam/75540-compressible-flow-solver-of1-6-a.html)

 mecbe2002 April 28, 2010 09:33

compressible flow solver in OF1.6

Hi all,

Why PISO & SIMPLE algorithms are used in OF for compressible flow problems. These algorithms are for pressure linked equation i.e. incompressible flows and for low Mach no flows.
Even density based solver "rhoSonicFoam" uses PISO algorithm why?

In compressible flows computation, we solve momentum equation to get velocity, energy equation to get temperature, density from continuity equation and pressure from perfect gas equation. correct me if i am wrong.
If this is the case, then why PISO & SIMPLE come into picture.

Thanks
mecbe

 truong_nm April 29, 2010 11:04

http://www.cfd-online.com/Forums/ope...mple-piso.html

Enjoy :)

 mecbe2002 April 29, 2010 12:52

Hi,

I read the thread and it was mentioned that steady state problem has to be solved by Pseudo Transient for stability. Can you give some details on it, because i am in the process of converting the "rhoSonicFoam" inviscid density based transient compressible flow solver(this doesn't uses PISO algorithm).

thanks
mecbe

 alberto April 30, 2010 01:07

Please, define the problem you want to solve, or we cannot give any specific answer. What is the Mach number, for example?

In addition, what do you mean with "converting" rhoSonicFoam? It is already a transient solver, and it doesn't use the PISO algorithm because it is density based.

Best,

 mecbe2002 April 30, 2010 01:17

Hi Alberto,

I want to solve transonic & supersonic inviscid steady flow over missile.
Mach No -0.9,1.2,1.8 & 2.5.

I saw the "rhoSonicFoam" code, it doesnt uses PISO algorithm, but in tutorial case file, it was there. sorry for that.

I want to convert it to steady state solver, bcz transient solver takes lot of time to converge.

One more question, can you explain about the slip boundary condition (other than given in the user guide).

Also, i want to implement some more inviscid flux discretization schemes like AUSM, HLLC.. Can you give some advice on how to carry on.

Thanks
mecbe

 alberto April 30, 2010 01:40

Quote:
 Originally Posted by mecbe2002 (Post 256945) Hi Alberto, I want to solve transonic & supersonic inviscid steady flow over missile. Mach No -0.9,1.2,1.8 & 2.5. I saw the "rhoSonicFoam" code, it doesnt uses PISO algorithm, but in tutorial case file, it was there. sorry for that. I want to convert it to steady state solver, bcz transient solver takes lot of time to converge.
You might want to take a look also to rhoCentralFoam and rhopSonicFoam.

Quote:
 One more question, can you explain about the slip boundary condition (other than given in the user guide).
What is not clear?

Best,

 mecbe2002 April 30, 2010 02:37

I will look into those two schemes.

What about implementing new inviscid flux computation schemes like AUSM, HLLC.

thanks
mecbe

 alberto April 30, 2010 12:06

Quote:
 Originally Posted by mecbe2002 (Post 256950) I will look into those two schemes. What about implementing new inviscid flux computation schemes like AUSM, HLLC. thanks mecbe
There's quite some work to do to be able to implement those. You might want to take a look at aeroFoam:

http://www.cfd-online.com/Forums/ope...-aerofoam.html

Best,

 mecbe2002 April 30, 2010 12:50

Hi Alberto,