CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (https://www.cfd-online.com/Forums/openfoam-solving/)
-   -   RAE2822 transonic aerofoil (https://www.cfd-online.com/Forums/openfoam-solving/106409-rae2822-transonic-aerofoil.html)

icedevill August 28, 2012 09:34

RAE2822 transonic aerofoil
 
2 Attachment(s)
Hi. I am currently trying to simulate the flow over a rae2822 aerofoil. This is a transonic flow and from what I've read in the forum one of the suggested solvers is sonicFoam. The mesh was build using gmsh and I've adapted the data in the 0 folder to best suit my configuration. The initial conditions are found http://www.grc.nasa.gov/WWW/wind/valid/raetaf/raetaf04/raetaf04.html . The problem is that my Cp pressure distribution is nothing near of the original experiment results. I have attached my 0, system and constant folder if this could help. Also i attached a chart of the distribution of the pressure. Thank you in advance

icedevill January 28, 2013 13:57

1 Attachment(s)
After much stress and searching around and help from others i got my simulation to work. The results are almost the same as other RAE2822 experiments, the only problem is that the shock is not where it is supposed to be. I attached a picture for reference. If anyone needs the case files, i will post them here. Also if you got any ideas about the shock, feel free to share them.

Corretelli May 22, 2013 12:55

I suspect a discrepancy between the case described in the NASA website
http://www.grc.nasa.gov/WWW/wind/val.../raetaf04.html
and the wind tunnel study. The boundary conditions (Mach 0.729, alpha = 2.31 degrees) seems not to correspond to any experimental results in the AGARD report.

Please see case #6 in the table on page 191 of:
Cook, P.H., M.A. McDonald, M.C.P. Firmin, "Aerofoil RAE 2822 - Pressure Distributions, and Boundary Layer and Wake Measurements," Experimental Data Base for Computer Program Assessment, AGARD Report AR 138, 1979.

(I do not recall where I downloaded the report some years ago....)

The boundary conditions on the another part of the NASA website do seem to match case #6 in the AGARD report.
http://www.grc.nasa.gov/WWW/wind/val...af/raetaf.html

Mach 0.725, alpha = 2.92 degrees

Good luck; I don't know if you are still checking this forum, but I hope this helps others who are doing validation.

- Corretelli

icedevill May 23, 2013 04:05

Indeed, the boundary conditions are different. I will simulate with the new values and maybe i will get an improvement. Thank you for your observations.

skeptik May 27, 2013 08:40

interesting
 
Quote:

Originally Posted by icedevill (Post 429429)
Indeed, the boundary conditions are different. I will simulate with the new values and maybe i will get an improvement. Thank you for your observations.

Hi.

I wait for your further simulations. I do airfoil at M>>0.3 too but it's NACA 23012 and i really interesting about your results.

But i have several questions about your case cause i didn't see mesh (there is empty polyMesh in the archive).

Which size is your domain?

It seems that you have small simulation time, so the solution is not "stationary".

icedevill May 27, 2013 09:04

I will attach an archive with what i did so far. The mesh was build using airfoilmesh2, a python script created by someone. The lengths of the domain, specified in the input script are:

-10 X_back control domain
5 X_front control domain
-5 Y_down control domain
5 Y_up control domain .

About the time: The deltaT in my controlDict file was the biggest i could find without crushing my simulation with an error. From what i read, finding the right deltaT is a matter of trial and error. Currently it is 4e-08, if i were to push it to 4e-07 for example, the simulation would crush. As a physical time i let it run for a couple of days as a single processor case.

Right now i am a bit caught between work and writing my dissertation, but i hope i will come with the new simulation results soon.

The archive is http://www.megafileupload.com/en/fil...e-diz-zip.html

skeptik May 28, 2013 03:35

Quote:

Originally Posted by icedevill (Post 430271)
-10 X_back control domain
5 X_front control domain
-5 Y_down control domain
5 Y_up control domain .

About the time: The deltaT in my controlDict file was the biggest i could find without crushing my simulation with an error. From what i read, finding the right deltaT is a matter of trial and error. Currently it is 4e-08, if i were to push it to 4e-07 for example, the simulation would crush. As a physical time i let it run for a couple of days as a single processor case.

I mean endTime of your simulation, not timeStep.

If you have domain size about 15 m, and U approx 240 m/s, you need endTime approx 0.06. But i think it would be better to set 0.12 or higher just wait till Cx or Cy becomes constant.

skeptik May 28, 2013 04:55

NACA 23012 results, transonic flow
 
3 Attachment(s)
What i've got about my airfoil (exp and Fluent data were extracted from article, but it's in russian. originally exp data from TZAGI report)

Attachment 22172

So there present oscillations, they were caused by second order schemes. I'll simulate it on upwind later.

The differences in p fields are showed here:

upwind
Attachment 22173

linear limited 1
Attachment 22174

also i will share my results obtained with sonicFoam, but later

PierluigiRossi December 16, 2014 04:19

RAE 2822 - Experimental measures
 
Dear all,

can someone send to me the following technical memorandum:

Cook, P.H., M.A. McDonald, M.C.P. Firmin, "Aerofoil RAE 2822 - Pressure Distributions, and Boundary Layer and Wake Measurements," Experimental Data Base for Computer Program Assessment, AGARD Report AR 138, 1979.

My email address follows:
kevin.kurany89@gmail.com

Thanks in advance. :)

BopngMa February 6, 2015 13:45

Quote:

Originally Posted by PierluigiRossi (Post 524149)
Dear all,

can someone send to me the following technical memorandum:

Cook, P.H., M.A. McDonald, M.C.P. Firmin, "Aerofoil RAE 2822 - Pressure Distributions, and Boundary Layer and Wake Measurements," Experimental Data Base for Computer Program Assessment, AGARD Report AR 138, 1979.

My email address follows:
kevin.kurany89@gmail.com

Thanks in advance. :)

Hello, have anyone sent you the AGARD Report? In my stimulation result, the
position of the shock wave also meet with the data of the experiment data. I want to check the report to find out the problems. Thanks

rfadlika October 5, 2015 00:04

Quote:

Originally Posted by icedevill (Post 404585)
After much stress and searching around and help from others i got my simulation to work. The results are almost the same as other RAE2822 experiments, the only problem is that the shock is not where it is supposed to be. I attached a picture for reference. If anyone needs the case files, i will post them here. Also if you got any ideas about the shock, feel free to share them.

Hi Alexandru Stroe,I am trying to run naca 0012 using sonicFoam, but I have no idea how to run using sonic Foam. Would you like to tell me if there is any tutorial?

Regards,

Ridwan

tjuwangrui December 24, 2015 04:58

Hello,I am trying to simulate the flow over a rae2822 aerofoil(Mach 0.729, alpha = 2.31 degrees),but the solution never satisfies the experimental data in NASA website,so I want to try another initial condition .
Cook, P.H., M.A. McDonald, M.C.P. Firmin, "Aerofoil RAE 2822 - Pressure Distributions, and Boundary Layer and Wake Measurements," Experimental Data Base for Computer Program Assessment, AGARD Report AR 138, 1979.
I also need the paper,but I never found it because of the long time.
Do you ever find it?If possible,would you mind sending it to me?thanks in advance.
tjuwangui@tju.edu.cn


All times are GMT -4. The time now is 14:07.