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High order panel modeling units?

  1. Dec 8, 2013 #1
    I have a copy of Pan Air (A502) which is a high-order panel method used for modeling 3D airflow around arbitrary bodies. I've read the manual, but I'm not clear about the units used. As I understand it, the free stream velocity is normalized which implies that all the other geometry is scaled by the same factor used to normalize the free stream velocity to a unit vector. No problem with that. But this is going to affect all the various factors it solves for, namely Cl, Cd, Cm, Cdi, and so on. There's also no place to enter the air density. So my question is how do I rescale the various coefficients to restore the units and take density into account?
     
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  3. Dec 9, 2013 #2

    boneh3ad

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    I am not familiar with that software, but the whole point of the force and moment coefficients is that they are supposed to be nondimensional and allow easy scaling of their respective quantities for a given set of dimensional conditions. Why do you feel you need to rescale them somehow?
     
  4. Dec 9, 2013 #3
    I understand that the coefficients are technically non-dimensional. But the program asks for things like span and area which is causing the reported numbers to change dramatically. It's pretty clear it's deriving the coefficients by dividing the forces by the area & span as needed, but the dimensions you need to give it is not clear. Plus, none of the input parameters reflect the dynamic pressure.

    It seems the model needs to be scaled by both the free stream velocity and by Q. However, no method is described in manual for doing this.
     
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