RAE2822 transonic aerofoil
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
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.
I suspect a discrepancy between the case described in the NASA website
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.
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.
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.
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".
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
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.
NACA 23012 results, transonic flow
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)
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:
linear limited 1
also i will share my results obtained with sonicFoam, but later
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