Hello, I have recently done a study to compare my simulated results with my calculated results on the naca 0012 airfoil. This study was to have a highly studied airfoil and simulate it and compare it with my calculated results. I have come across a few interesting finds along the way too.
here is the project link so you can check it out yourself please don’t edit - https://www.simscale.com/workbench/?pid=8117823371083257521&rru=857bb23d-c8fe-498d-9400-077d8115ce29&ci=f30d0f1a-1b51-4702-a4f3-187dfff5c40c&ct=SOLUTION_FIELD&mt=SIMULATION_RESULT
I have used an airfoil add-on in Fusion 360 to create the airfoil profile, extruded it, and then imported it as a .STEP file. I ran a simulation once with the standard mesher and then ran 2 simulations with the hex dominant meshes
For the results, the expected results were 0 N for lift and got -0.01 N for the standard mesher, I think this is pretty good. For the hex dominant, I got 0.1 N of lift which is a little less accurate but not too bad(I have not been able why there is a big difference like this, my guess is that when you have a 3d airfoil it is different than inputting the CL and CD in the lift and drag equation, maybe someone else has an idea why this is happening?).
Now that we have done the lift, it is time for the more interesting part, the drag.
The expected results were 0.309 N based on xfoil predictions and airfoil tools charts. The simulated results for the viscous force was 0.33 N and for pressure was 0.1121 N. Now the viscous force seemed very close to the predicted drag but there is still pressure force to be accounted for. This leads me to believe that xfoil and airfoil tools have correct charts, what probably is happening is that they are either( a - both accounting for pressure just not accounting for other sources of drag because the wing is finite in the 3d world.), (b - they don’t account for pressure force), or (c - the simulation is wrong and someone please tell me why.). The standard mesh gave me around the same results for the drag.
here is a picture of the written results
here is a picture of the pressure forces acting on the plane
overall I think this was a really cool project and would appreciate some feedback on why the results were that way.