Is there a correlation between the lift coefficient and the proximity between the wing and the ground? I know that the lift coefficient is dependent on angle of attack; However, based on experiments that I have conducted, the results disproved the claim somehow, at the same angle of attack (0 degrees), the lift generated is higher when in ground effect than out of ground effect. Based on the experiment, given that wind velocity, wing span and density (according to the ISA) is the same, does this meant that ground effect (proximity when in ground effect) can bring a change in lift coefficient? Moreover, is there a specific correlation,is it linear or exponential?
It is really weird how I can find literally anything but the correlation between proximity and lift (or lift coefficient), there are essay on how ground effect affects forward swept wing aircraft, and yet there's not a single essay about proximity and lift coefficient :(