How to use SUAVE.Analyses.Aerodynamics.Fidelity_Zero()

[Chang]

Hi, I have studied SUAVE for one month and created a new small UAV by myself. And now, I want to do a simple aerodynamic analysis at a given speed, pressure, temperature, viscousity, and several angles of attack (such as from -10°  to 10°) by using SUAVE.Analyses.Aerodynamics.Fidelity_Zero(). Maybe just like a point analysis without mission. The code could be  runned successfully without any warning or error, but there are obvious mistakes in results. The aerodynamic force coefficiet (CL, CD) are totally same  at AOA -10°, -8°, -6°. The results at other AOA close to results calculated by OpenVSP, but don't match well.

I also found the code https://github.com/suavecode/SUAVE/blob/develop/regression/scripts/aerodynamics/aerodynamics.py, and modificated my code follow the scripts, but didn't work. I noticed the differences in state.conditons. Only one speed, one pressure, one temperature, one viscousity and 11 angle of attacks are given in my code, but all the parameters and results(lift coefficient, drag coefficient, etc.) are 11 in aerodynamics.py. There is an annotaton for given parameters, "Initialize variables needed for CL and CD calculations.# Use a pre-run random order for values", how does these values being determined? How these conditons corresponding to finial results in aerodynamics.py ? Or the final results corresponding to which conditon(velocity, pressure, temperature, Reynolds number)?

Looking forward  to your reply.

Best regards.

Chang

[Emilio]

You definitely should be seeing different force coefficients. Try updating your settings, this one specifically. SUAVE doesn't query the surrogate model at highly negative AoA's, try adding those.

That script is an excellent starting point. The note about pre-run random order is exactly that, we picked some random conditions for our test case. The final results correspond to the velocity/pressure/temp/Re etc... viscous results require those.

You should be seeing 11 results because you have 11 AoAs? Or is it 11x11? That can happen if two arrays are not the same shape (1,11) and (11,1).

-Emilio

[Chang]

Thank you for your advices, I have found the training settings of surrogate model. But I'm still confused about the result. The result(such as total lift coefficient) and AoA are 11×1, it seems the result correspond to AoA, but velocity, pressure, temperature, Re are also 11×1, which value in velocity/pressure/temperature/Re arrays are correapond to the result?

Chang

[Emilio]

Hi Chang,

That's correct, think of each item in the array corresponding with a different point in a flight. The velocity/pressure/temperature/Re would all change as you fly. If you want to hold quantities constant while changing others you may do so.

-Emilio