Explaining the large variability in empirical relationships between magnetic pore fabrics and pore space properties

SUMMARY The magnetic anisotropy exhibited by ferrofluid-impregnated samples serves as a proxy for their pore fabrics, and is therefore known fabric (MPF). Empirically, the orientation of maximum susceptibility indicates average elongation direction, predicts preferred flow direction. Further, correlations exist between degree shape pores’ axial ratio shape, degrees permeability anisotropies. Despite its potential, method has been rarely used, likely because large variability in reported empirical relationships compromises interpretation. Recent work identified an additional contribution distribution anisotropy, related to arrangement pores, strong dependence parameters on ferrofluid type concentration, partly explaining variability. Here, effect shown; effective depends measurement frequency, so that resulting conditions. Using synthetic with void geometry ferrofluids (4.04 SI 1.38 EMG705 EMG909, respectively), measurements at frequencies from 500 512 kHz are compared numerical predictions. Measurements show frequency-dependence, especially EMG705, leading discrepancies measured calculated degrees. We also observe artefacts interaction seal, aggregation particles over time. results presented here provide basis robust quantitative interpretation MPFs future studies, allow re-interpretation previous provided properties conditions known. recommend experimental settings selected ensure high intrinsic fluid, fluid studies.