Hi,

What are these Aerodynamic Influence Coefficents and how we can get these from Unsteady pressure distribution using FFT.

Thanks

Are you talking about something Aeroelastic or just Aerodynamic?

That's related to AeroElasticity

hi, have a look at www.aero.polimi.it/~cavagna under the publications section. Luca

I'm not able to go further because it's not my field. You should follow the Luca's link.

Hi,

Thanks a lot, I will be looking on these papers.

Thanks,

That might help!

The classic definition of aerodynamic influence coefficients is that the the A_ij component of the coefficent matrix relates the velocity potential at a point "i" to the "downwash" w at a point j(normal velocity on the wing) ie:

phi_1=A_11*w_1+A_12*w_2+A_13*w_3+..... phi_2=A_21*w_1+A_22*w_2+...

etc

you can also think of them as relating the force at point f_i to the downwash at a point j ie

f_1=B_11*w_1+B_12*w_2+B_13*w_3+..... f_2=B_21*w_1+B_22*w_2+...

the A_ij(and B_ij) are functions of Mach number and reduced frfequency.

As far as determining them from unsteady pressure measurements you would need additional data such as surface velocities I believe. A search of the literature should come up with numerous methods for approximation these coefficients numerically.