Negative Induction factors

Is it possible to obtain negative axial and tangential induction factors in blade element moment theory. I have written my own BEMT code in matlab and applied Prandtl’s tip and root correction and Glauret’s correction for high values of axial induction factor. But i am getting negative values for both factors for some elements(near root).

Dear Zeeshan,

It is possible, but a negative axial induction factor represents the “propeller” region instead of the “wind turbine” region.

Best regards,

Thanks a lot. I figured it out. There was a bug in my code.