Magnetoviscosity of dilute suspensions of magnetic ellipsoids obtained through rotational Brownian dynamics simulations

Transient magnetoviscosity of dilute ferrofluids

“…All runs were performed starting from a random configuration, using 10 5 non-interacting particles, a time step oft ¼ 0:01, Langevin parameters of a¼1, 5, 10, and dimensionless shear rates of Pe¼1, 5, 10. The intrinsic magnetoviscosity Z m zy h i for a dilute suspension was evaluated as in [7]. For spherical particles the intrinsic magnetoviscosity is then…”

Oscillatory shear response of dilute ferrofluids: Predictions from rotational Brownian dynamics simulations and ferrohydrodynamics modeling

“…In order to reduce the number of variables in the angular momentum equation, time was nondimensionalized with respect to the rotational diffusion coefficient D r = k B T (η 0 K r ) −1 , and the vector variables were nondimensionalized with respect to their magnitudes [15]. Setting d˜ =ω dt, where d˜ is the infinitesimal rotation vector, integrating from timet tot + t using a first-order forward Euler method and applying the fluctuation-dissipation theorem to the Brownian term [50], we obtain…”

“…The magnetorheology of ferrofluids has been an active area of experimental [1][2][3][4][5][6] and theoretical [7][8][9][10][11][12] research for decades. The focus of most work has been the steady-state response of dilute and semidilute ferrofluids to imposed constant shear and magnetic fields [2,3,[13][14][15][16][17][18][19][20][21]. There has also been some work on the response of ferrofluids to oscillating [3,14,[22][23][24][25][26] and rotating [14,[27][28][29][30][31][32] magnetic fields; however, here again a steady flow has been considered.…”

Brownian dynamics simulation of a dispersion composed of disk-like hematite particles regarding the orientational distribution and the magneto-rheological properties

“…Ordinary magnetic particles are ferromagnetic, as in the case of magnetite, and they are usually magnetized in the particle axis direction, which gives rise to the significant orientational feature of a single-peak orientational distribution under the circumstance of an applied magnetic field and a flow field [25][26][27][28][29][30][31]. In contrast, hematite particles exhibit quite different characteristics because they are magnetized in a direction normal to the particle axis direction, and exhibit much weaker magnetization than magnetite [32][33][34][35].…”