From reading the paper I am skeptical. Several years ago, similar (published) claims were made about induced drag savings from highly sheared wing tips. It turned out that the drag savings were an artifact of the computational method (predicted drag became very sensistive to panel spacing as the leading edge sweep increased). The paper did not go into detail as to whether the researchers investigated different panel geometries or densities in this case.

The article refers to wind tunnel testing. I think the Physics of Fluids paper will be enlightening. It will be interesting to see how this work holds up in the stark light of peer review.