How and where to define a 2d airfoil?

[KlausB]

Hello,

I’d like to validate the program for the eppler 322 airfoil lift/drag calculations at Re 70.000, 100.000 and 120.000.

Airfoil profiles are defined by a set of x/y coordinates, usually in xfoil format:

e344
1.00000 0.00000
0.99260 0.00158
0.97950 0.00493
0.96379 0.00894
0.94629 0.01290
0.92677 0.01682
0.90551 0.02083
0.88324 0.02496
0.86055 0.02918
0.83776 0.03344
0.81500 0.03770
…
0.94774 -0.00309
0.96472 -0.00128
0.97968 -0.00020
0.99250 0.00015
1.00000 0.00000

The curve (spline) starts at the trailing edge, creates the top towards the nose and then the bottom back towards the trailing edge.

How and where should I define the airfoil shape? How can I change the angle-of-attack (AOA)?

Klaus

[mathias]

Dear Klaus,

I think you need to program this by hand.. But we had a paper on that topic, so you may kontact my Australian friend for help:
2016, N. Nadim, T.T. Chandratilleke and M.J. Krause. LBM-LES Modelling of Low Reynolds Number Turbulent Flow Over NACA0012 Aerofoil. In: Fluid-Structure-Sound Interactions and Control. Ed. by Yu Zhou, A.D. Lucey, Y. Lis and L. Huang. Lecture Notes in Mechanical Engineering. Springer Berlin Heidelberg, 2013, pp. 205-210, 2016.

If the compiling did work, please say that in the forum that other people will not face the some problem again.

Best
Mathias

[KlausB]

Hello Mathias,

I didn’t get any feedback but maybe we can adapt the xfoil approach.

Please have a look at: https://github.com/RobotLocomotion/xfoil/blob/master/src/spline.f

The fortran code includes several options/implementations maybe let’s just go for the first one.

What do you think? How to approach it?

Klaus

[mathias]

Dear Klaus,

basically you need to program an indicator which return true if a given coordinate (x,y) is within an object and false if not.

Best
Mathias

[Author]

Posts