where G is the complex material modulus.
From the formula (1) it is evident, that in order to
determine how external magnetic field influences magneto-
rheological fluid’s pressure loss, it is needed to determine
yield stress y . In majority of magneto-rheological
fluid’s paperwork there is graphs presenting yield stress vs.
magnetic field strength, therefore, once magnetorheological
fluid‘s magnetic field strength is calculated,
yield stress figures are available.
To determine magneto-rheological fluid‘s and
Magnetic field Strength (H) a Femm 4.2 program was
used. The program enables solving low frequency electromagnetic
problems on two-dimensional planar and axisymmetric
domains [9].