Induction current- velocity dependence

[dave8]

Hello,

I have to put the cylindrical permanent magnet into shaft of the shock absorber with coil around it. I need such a system which let's me to control the damping coefficient of the shock absorber so that's why a have to know the current. I can't find anywhere the relation between induction current and for example velocity of linear movement of the shaft, by the use of Faraday's Law I found that it should be that
E = vxB(Rext-Rint)
where E - electromotive force, v - velocity, B - magnetic field induction, Rext - external radius, Rint - internal radius of the magnet
But I don't think that its true because B and v vectors have the same direction.
Please help

 

[anorlunda]

Calculating the forces on permanent magnets is a notoriously difficult problem. You will need the assistance of a software package like ANSYS Maxwell.