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May 1, 2011, 09:33 
NACA0012 with rhoCentralFoam

#1 
Super Moderator

I am having some problem with a NACA0012 test case using rhoCentralFoam. The freestream mach is 0.75 and there is a shock. I have attached some pictures. There is something wrong with the bcs.
Some of the input options are listed below. Other input files are same as here http://gfoam.svn.sourceforge.net/vie...12_7k_M075_a2/ Hope somebody can point out the mistakes. 0/p Code:
internalField uniform 85418.9; boundaryField { inletoutlet { type fixedValue; value uniform 85418.9; } body { //type slip; type zeroGradient; } defaultFaces { type empty; } } Code:
internalField uniform 260; boundaryField { inletoutlet { type fixedValue; value uniform 260; } body { //type slip; type zeroGradient; } defaultFaces { type empty; } } Code:
internalField uniform (242.284 8.46075 0); boundaryField { inletoutlet { type fixedValue; value uniform (242.284 8.46075 0); } body { type slip; } defaultFaces { type empty; } } Code:
thermoType ePsiThermo<pureMixture<constTransport<specieThermo<eConstThermo<perfectGas>>>>>; mixture air 1 28.965 717.625 0 0 0.72; 

May 1, 2011, 14:32 

#2 
Senior Member

hi praveen,
Is the solution converges well and where can i really see that you used the rhoCentralFoam for your problem. 

May 1, 2011, 22:13 

#3 
Super Moderator

Everything in the above link remains same for rhoCentralFoam except you have to change to
fluxScheme Kurganov; // or Tadmor in system/fvSchemes. The files can be downloaded here http://gfoam.svn.sourceforge.net/vie...5_a2/?view=tar 

June 3, 2011, 05:07 
NACA0012 with rhoCentralFoam

#4 
Senior Member
NAVEEN.K.M
Join Date: Mar 2009
Location: Bangalore, Karnataka, india
Posts: 114
Rep Power: 9 
hi praveen,
I am also trying for different airfoil simulation using rhoCentralFoam using different boundary condition at mach no=0.7. even i am also getting same error wat u r getting on airfoil surface for unstructured grid. But when i solved for structured grid (same airfoil wat i used for unstructured) i am getting perfect solution using rhoCentralFoam for C Grid without any disturbances on airfoil surface. Could you please tell me what s da solution for this type of problem, if u have solved..... Regards NAVEEN.K.M NAL BANGALORE 

June 3, 2011, 05:27 
NACA0012 with rhoCentralFoam

#6 
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NAVEEN.K.M
Join Date: Mar 2009
Location: Bangalore, Karnataka, india
Posts: 114
Rep Power: 9 
OK....letś try some other way....can u give me your mail id....
NAVEEN.K.M Last edited by naveen; June 8, 2011 at 05:59. 

June 8, 2011, 06:01 
NACA0012 with rhoCentralFoam

#7 
Senior Member
NAVEEN.K.M
Join Date: Mar 2009
Location: Bangalore, Karnataka, india
Posts: 114
Rep Power: 9 
hi praveen,
I got the proper results for airfoil using rhoCentralFoam for unstructured grid same as structured grid. Regards NAVEEN 

July 28, 2011, 12:00 

#8 
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TCH
Join Date: Jul 2010
Location: Beijing City
Posts: 15
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Hi guys, I encountered the same problem, could you please tell me how do you solve the problems on unstructured grid? Thanks a lot!~


July 28, 2011, 12:42 

#9 
Super Moderator


July 28, 2011, 21:31 

#10 
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venkat
Join Date: Mar 2011
Location: Bangalore,india
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can anybody provide details about preconditioning for the above solver for Mach number approaching zero.
thanks in advance, Regards. 

July 29, 2011, 00:36 
for the mach number approaching to zero

#11  
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TCH
Join Date: Jul 2010
Location: Beijing City
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Quote:
regrads. TCH 

July 29, 2011, 03:49 
hi

#12 
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venkat
Join Date: Mar 2011
Location: Bangalore,india
Posts: 47
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solvers for compressible flows always has Mach number is greater than that of incompressible flows, using preconditioning we can use compressible flow solvers for solving incompressible NS equations ( having Mach Number nearer to zero)
can anybody provide details about the code to implement in openFoam. here I am attaching the link which contains the details about the method. http://openfoamwiki.net/index.php/TestLucaG. thanks in advance regards. 

December 7, 2011, 23:49 

#13 
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Daniel
Join Date: Jul 2009
Location: Montreal, Canada
Posts: 154
Rep Power: 9 
Hello all,
I am trying to simulate a NACA 0012 airfoil in transonic flow. I believe that rhoCentralFoam would be the best solver for the compressible & transient simulations. However, I have not used a densitybased solver before and I am struggling with a few issues: 1. What is the best way to check for convergence? When using simpleFoam, I plotted Ux_0 and p_0 residuals. In rhoCentralFoam, there is no p_0 residual (obviously) and the rho_0 residual is 0 from start to finish. 2. Here is what a typical timestep looks like in the log. I find it strange that all of the rho equations have 0 residual and 0 iterations. Any advice? Code:
Mean and max Courant Numbers = 0.00853124 0.92921 deltaT = 4.19687e07 Time = 8.52996e07 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0 diagonal: Solving for rhoUy, Initial residual = 0, Final residual = 0, No Iterations 0 smoothSolver: Solving for Ux, Initial residual = 3.21903e06, Final residual = 2.88895e09, No Iterations 2 smoothSolver: Solving for Uy, Initial residual = 2.167e06, Final residual = 5.51926e09, No Iterations 2 diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0 smoothSolver: Solving for e, Initial residual = 5.09557e06, Final residual = 1.47595e08, No Iterations 2 smoothSolver: Solving for omega, Initial residual = 3.91917e06, Final residual = 3.3493e10, No Iterations 2 bounding omega, min: 6231.35 max: 239456 average: 1107.8 smoothSolver: Solving for k, Initial residual = 0.00250408, Final residual = 1.13916e08, No Iterations 2 ExecutionTime = 0.28 s ClockTime = 0 s Thank you for any suggestions, Dan 

December 12, 2012, 04:02 
same question for zero density

#14 
Member
Farshad
Join Date: Oct 2010
Posts: 76
Rep Power: 8 
Hi,
Is there anybody who can help us with this question because many good people have asked it and no one has ever replied properly. Kind Regards, Farshad 

December 12, 2012, 04:16 

#15 
Super Moderator


December 12, 2012, 04:33 
how about kurganovtadmor or AUSM+?

#16 
Member
Farshad
Join Date: Oct 2010
Posts: 76
Rep Power: 8 
Hi,
I read that and he mentioned that: "The obliqueshock and forwardstep cases run fine but there is some problem with the naca case. The case runs but the solution has strange behaviour near airfoil surface " So i think the airfoil is a problem but why? The other problem is that the kurganovtadmor or any other flux scheme is not available. Kind Regards, Farshad 

July 11, 2013, 08:29 
naca0012 rhoCentralFoam instabilities

#17 
New Member
Johan
Join Date: May 2012
Posts: 5
Rep Power: 6 
Hi,
Using Vuorinen's slides on "Compressible RungeKutta 4 LESSolver to OpenFOAM", I implemented RK in rhoCentralFoam. This seems to provide a notable improvement in removing those numerical instabilities. I am still using vanLeer in fvScheme and not gamma. Regards Johan 

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