EMF on moving bar when it is shielded from magnetic induction

Fig.: Conductive bar moving along a conductive rail. The bar is
shielded from magnetic induction by a highly permeable, insulated cylinder.

I know if a conductive bar moves on a conductive rail
with velocity v through a constant magnetic field B then the
induced voltage is $vlB$.
($v,l,B$ are perpendicular each other, and the length of bar denoted by $l$)
This phenomena generally explained by $F=(q vtimes B)$ Lorentz force on a moving charge in field B.

But how could I understand that the induced EMF will be same $(vlB)$ even if the
bar is shielded from magnetic induction by a highly permeable, insulated cylinder.
Inside the cylinder there is only a few percent of $B$ since $μ_r$ is large.

I tried to understand it from this paper:
A Note on Faraday Paradoxes
IEEE Transactions on Magnetics, vol. 50, no. 2, February 2014
tmp.link helps in fast access for the above paper.

They are using the "modified" Stoke’s low because there is discontinuity
of $B$ on surfaces at the inner and outer diameters of the permeable cylinder.
In this paper the reference for this phenomena unfortunately in German language.

Can anybody give me a more detailed explanation and/or title of book for this and like this induction phenomena?
And what can I know from electron distribution in the moving bar (both shielded or unshielded case) if we didn’t close the circuit externally with the voltmeter ?