[swaze]

Hi guys,

i am doing a project on naca0012 of 1m chord length in ansys cfx with the following properties
- incompressible, subsonic turbulent flow (air)
- Reynolds no = 26e+5, free stream v = 40m/s, ref pressure = 101 kPa, static pressure 293K
- with an inflation layer (based on height of first boundary layer to wall) of 8.3e-5 m.
but the result I got doesn't convince me, especially for the velocity contours the cL and cD plots.
would there be an issue on the set up that i use that have an effect on this?
SET UP
isothermal at 20 degrees C (is this correct), as i know compressible flows are done with total energy.
I am using SST turbulence model


please find attached file of the plotted contours.
any guidance will be helpful, thank you very much

[ghorrocks]

There is an FAQ on accuracy: https://www.cfd-online.com/Wiki/Ansy..._inaccurate.3F

Looking at your results you appear to have some fundamental problems. Your velocity contours show high velocity at the top of your domain and low at the bottom. What is doing that? That does not look right.

On your pressure contours you have a bubble of high pressure at the top left corner and a bubble of low pressure in the bottom left corner. Again, this is not right.

And finally, this should be an incompressible flow and Mach Number is not defined. But you are showing Mach number - so are you actually doing a compressible simulation? Is this what you intended?

Please post your Output file so we can check it.

[urosgrivc]

try reconsidering the domain size,
probably this is the cause of weird velocity contour and other results of course.
Farr field boundary conditions must not influence your results, the solution must be independent of certain BCs.

unless you want to include the tunnel to make some kind of real comparison study or what