Enhancement of viscosity increase for alumina nanofluids as a function of volume fraction of nanoparticles. S1 (diamond) and S2 (triangle) samples. Prediction of Einstein equation (broken solid line), Equation 3 with N = 1 (dashed line), Equation 5, considering variable aa/a ratio (dashed-dot line), and Equation 5 considering constant aa/a ratio (solid line).
Pastoriza-Gallego et al. Nanoscale Research Letters 2011 6:221 doi:10.1186/1556-276X-6-221