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[ANSYS Meshing] How to create a 2D parabolic mesh for an aerofoil??

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Old   September 4, 2016, 13:07
Default How to create a 2D parabolic mesh for an aerofoil??
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Abhishek Gajare
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Hey Friends,

Simple question, even though I couldn't find it in the history of threads under the same section.

How to create a parabolic mesh just like the one in the ANSYS Tutorial file for "external compressible flow", 'airfoil.msh' (attached image)??
I am trying to create a similar mesh for a NACA0012 aerofoil (related to my thesis project), since I too am performing a compressible flow (transonic) analysis and believe this mesh configuration to be the best for such flow conditions. Correct me if I am wrong.

Thank you for any help or guidance you may offer. In the community I trust!!

Cheers!

-AMG
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Old   September 6, 2016, 04:58
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Paritosh Vasava
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Checkout these tutorials.

https://confluence.cornell.edu/displ...ver+an+Airfoil

https://confluence.cornell.edu/displ...+Specification
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Old   September 6, 2016, 13:02
Smile Thanks !! But...
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Thank you for the links Mr. Vasava, but I am looking to generate a Parabolic mesh in particular. The C-Mesh is the most common (and easiest, i guess) one used for most 2D aerofoils. My guess is that a parabolic mesh suits the external compressible flow condition better (and gives better accuracy of results); correct me if I am wrong.

Cheers!
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Old   September 12, 2016, 13:53
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I have been trying to replicate the parabola in my own creative ways, but I am just not able to draw it as neat as it is in the tutorial file. If somebody has any suggestions on how to improve my skills with the spline tool, you're welcome.

Thanks in advance.
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Old   September 13, 2016, 02:26
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Paritosh Vasava
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What I usually do is draw a large ellipse, get the bluff-body close to one of the foci and cut the extra part that I dont need.
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Old   September 18, 2016, 02:39
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@Vasava: Thanks for the suggestion. I must admit, it works really well. But I also tried creating a parabolic geometry myself (by using Splines, phew!) and it turns out there isn't much of a difference between the results from using the two methods.
My concern now is improving the 'Orthogonal Quality' of the mesh (the stat that appears when you click "Report Quality") as it is somewhere around 0.1 and remains the same even if I increase the 'number of elements'. I read that somewhere around 0.5 is acceptable. I am assuming that it is because of the skewness of my mesh around the frontal portion of my bluff body (I like to call it aerofoil) (as shown in attached image). The image I shared earlier (of "airfoil.msh") doesn't seem to have this sort of skewness. The elements are almost perpendicular to the surface. How can I achieve the same??
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Old   September 18, 2016, 11:09
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Hey ,

I am in a real fix right now with this mesh of mine . If I increase the number of cells (mostly around the aerofoil/bluff body) the residuals are diverging . The message is mostly regarding the 'Turbulent Viscosity Ratio' being limited for a given number of cells to 1E05.

Also, I am having a strong feeling that the orthogonal quality has a lot to do with the convergence of my mesh.

Let me tell you all, I am trying to re-create an experimental setup (by C.D.Harrris of NASA on Transonic Flow about NACA0012 aerofoil at different mach & Reynolds numbers) within ANSYS-FLUENT. So basically I have the experimental results in terms of Cp (Pr. coefficient) vs x/c graphs and I am trying to obtain similar results out of my FLUENT computation.
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