What is formula for induced drag in stalling regime? I'm wondering what is the formula for induced drag in a stalled regime, i.e. in a regime where the $C_L$ (coef. of. lift) has started to decrease but is still nonzero.

I've a feeling that the conventional formula for induced drag
$$D_i = \frac{L^2}{\frac{1}{2}\rho V^2   \pi b^2 \epsilon}$$ (taken e.g. from this answer) which in essence depends on lift $L$, does not explain induced drag in stalling regime (if it would, it would erroneously imply that the induced drag is equal for a pair of AoAs $\alpha_{\text{before-stall}} &lt; \alpha_{\text{after-stall}}$ which both correspond to the the same $C_L$).

I've come across the evidence that induced drag continues to grow as square of AoA even in stalled regime (e.g. schematic Fig. 4.14 from av8n.com) 



but can't find more.

Thanks.
That formula describes the "lift-induced drag" for a planar wing. Lift-induced drag

As the definition implies, this drag is induced by the generated lift, the effect of stall (flow separation) is not contributing to this drag component.

Therefore, there is no other formula for the stalled regime.