High-speed videomicroscopy and magnetorheology under triaxial unsteady magnetic fields.

Martínez-Cano, O; Morillas, J R; Ruiz-Nievas, J; Camacho, G; Rodríguez-Barroso, A; Ramírez, J; de Vicente, J · Phys Rev E · 2025

basic_science · Level V

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Abstract

We describe a custom-built device that is capable of superimposing triaxial unsteady magnetic fields on a sample at the same time that its microstructure is visualized using a high-speed camera and its rheological properties are measured with a commercial rheometer. The device reaches field strengths up to 5 kA·m^{-1}, frequencies up to 4 kHz, and its functionality is evaluated by testing magnetorheological fluids under steady shear flow and field transients. Striking differences are found at small Mason numbers by changing the field configuration.