[PhilipA]

Hello All,

I’m quite new to SU2 and I have been struggling to recreate experimental data for a NACA0021 airfoil. I have only managed to achieve a maximum lift/drag ratio of 4. However, the data I am trying to recreate has a lift to drag ratio of 23 (at 10° AoA). Link: https://www.researchgate.net/profile...1-aerofoil.pdf. I have based my config file on the Turbulent NACA0012 tutorial code. Link: https://su2code.github.io/tutorials/...lent_NACA0012/.

Here's a list of things I have tried so far:

• Changing initial velocity to 50 m/s
  
• Changing CFL to 50
  
• SA & SST Turbulence model
  
• FDS & Roe convective numerical methods
  
• Looking through the config file and the guidelines in the SU2 documentation
  
• Checked that my CV Face Area aspect ratio was not too high (recommendation from this forum post. Link: Experimental values not matching SU2 values)
  
• Altering the mesh to be 500 chord lengths away from the airfoil (according to NASA’s guidelines for the NACA0012 Validation. Link: https://turbmodels.larc.nasa.gov/naca0012_val.html) -
  • Note: This was with an INC_RANS solver, SA turbulence model & FDS convective numerical method
  • Improved lift/drag ratio from 3.13 → 4.0 (max I’ve been able to achieve)
  • Also it took 3 hours to run 28 iterations due to the size of the mesh

I’ve attached my config file, mesh & an image of the mesh quality generated (I could not attach the 500c mesh as it was too big)

• NACA-0021 is the default mesh I use (~7-8c farfield distance)

I’m thinking it is something to do with my configuration settings, however I’m not sure what it could be.

Any help would be greatly appreciated,

Thanks

Philip

[PhilipA]

I believe I may have found a potential source of the issue.

It seems that joining the airfoil up with normal lines is creating a jagged profile so I have tried to create an airfoil using multiple different curve types (B-spline, Spline and Bezier). However, the mesh does not recognise the airfoil boundary when I use these curves. Here is the script used (Bezier curve):

//+
Point(1) = {1.0, 0.00221, 0, 1.0};
//+
Point(2) = {0.95, 0.01412, -0, 1.0};
//+
Point(3) = {0.90, 0.02534, -0, 1.0};
//+
Point(4) = {0.8, 0.04591, -0, 1.0};
//+
Point(5) = {0.7, 0.06412, -0, 1.0};
//+
Point(6) = {0.6, 0.07986, -0, 1.0};
//+
Point(7) = {0.5, 0.09265, -0, 1.0};
//+
Point(8) = {0.4, 0.10156, -0, 1.0};
//+
Point(9) = {0.3, 0.10504, -0, 1.0};
//+
Point(10) = {0.25, 0.10397, -0, 1.0};
//+
Point(11) = {0.2, 0.1004, -0, 1.0};
//+
Point(12) = {0.15, 0.09354, -0, 1.0};
//+
Point(13) = {0.1, 0.08195, -0, 1.0};
//+
Point(14) = {0.075, 0.0735, -0, 1.0};
//+
Point(15) = {0.05, 0.06221, -0, 1.0};
//+
Point(16) = {0.025, 0.04576, -0, 1.0};
//+
Point(17) = {0.0125, 0.03315, -0, 1.0};
//+
Point(18) = {0, 0, -0, 1.0};
//+
Point(19) = {0.0125, -0.03315, -0, 1.0};
//+
Point(20) = {0.025, -0.04576, -0, 1.0};
//+
Point(21) = {0.05, -0.06221, -0, 1.0};
//+
Point(22) = {0.075, -0.0735, -0, 1.0};
//+
Point(23) = {0.1, -0.08195, -0, 1.0};
//+
Point(24) = {0.15, -0.09354, -0, 1.0};
//+
Point(25) = {0.2, -0.1004, -0, 1.0};
//+
Point(26) = {0.25, -0.10397, -0, 1.0};
//+
Point(27) = {0.3, -0.10504, -0, 1.0};
//+
Point(28) = {0.4, -0.10156, -0, 1.0};
//+
Point(29) = {0.5, -0.09265, -0, 1.0};
//+
Point(30) = {0.6, -0.07986, -0, 1.0};
//+
Point(31) = {0.7, -0.06412, -0, 1.0};
//+
Point(32) = {0.8, -0.04591, -0, 1.0};
//+
Point(33) = {0.9, -0.02534, -0, 1.0};
//+
Point(34) = {0.95, -0.01412, -0, 1.0};
//+
Point(35) = {2.5, 50, 0, 1.0};
//+
Point(36) = {2.5, -50, 0, 1.0};
//+
Point(37) = {2.8, 0, 0, 1.0};
//+
Circle(34) = {35, 37, 36};
//+
Point(38) = {50, 50, 0, 1.0};
//+
Point(39) = {50, -50, 0, 1.0};
//+
Line(35) = {35, 38};
//+
Line(36) = {38, 39};
//+
Bezier(37) = {1, 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 1};
//+
Line(38) = {36, 39};
//+
Physical Curve("farfield", 39) = {34, 35, 36, 38};
//+
Physical Curve("airfoil", 40) = {37};
//+
Curve Loop(1) = {35, 36, -38, -34};
//+
Curve Loop(2) = {37};
//+
Plane Surface(1) = {1, 2};

I'll also attach an image of the mesh going through the airfoil

Any help would be much appreciated!