Hi,

Apologies if this has been asked before, I have had a quick search but haven't quite found the answer I was after.

I am currently doing a thesis on the design of a rear wing for a formula student car. I am currently trying to validate my results for a 2D flow simulation of a NACA 0012 profile using data provided on the NASA website http://turbmodels.larc.nasa.gov/NACA0012_validation/CLCD_Ladson_expdata.dat

I have good correlation until about 13 degrees where it seems to tail off. You can see a rough graph comparing the wind tunnel data to my solidworks results below.

In order to simulate the angle of attack I have the airfoil sitting parallel with the meshline, and I select the angle of attack in the general settings.

Now to calculate the lift coefficient, I insert a global goal for the Normal Force (Y), and then insert an equation goal to calculate the lift coefficient. However, one thing I recently became aware of is that the Normal Force (Y) is always perpendicular to the airfoil, rather than perpendicular to the flow, which is what I want to know.

Is there a way that I can calculate the lift coefficient for the wing, perpendicular to the flow rather than perpendicular to the airfoil?

Also, if there are any other suggestions that might help me please feel free to share!

Thanks

Nathan,

You have the right idea in keeping your mesh consistent and parallel to the major axis of your wing, that seems to be the best way of going about it given that we are constrained to an orthogonal mesh in this software. Your results seem consistent with what others have posted on this forum regarding airfoils, the software always seems to diverge from established datasets once the angle of attack goes past 10-12 degrees.

As for your forces, you could calculate your lift and drag relative to the angle of attack using an equation goal. The problem is that I do not believe we can set variables within Flow Sim, so your equation goals would have to use a scalar value for the angle which would of course only be valid for that particular simulation. I think your best bet is to just get the lift and drag forces relative to the flow sim coordinate system, and then recalculate the lift and drag relative to the angle of attack in your data analysis spreadsheet. That's just basic vector math so you shouldn't have a problem with it.