Bistability and metabistability scenario in the dynamics of an ellipsoidal particle in a sheared viscoelastic fluid

摘要: The motion of an ellipsoidal particle in a viscoelastic liquid subjected to unconfined shear flow is addressed by numerical simulations. A complex dynamics found with different transients and long-time regimes depending on the Deborah number De (De product intrinsic time times applied rate). Spiraling orbits toward log-rolling around vorticity are observed for low numbers, whereas aligns its major axis near direction at high numbers. transition from alignment characterized periodic regime small amplitude oscillations orientations progressively shifting increasing De. range numbers detected such that solution coexists (bistability). further where attained differently particles starting far or next plane: latter case, very long found; hence effective bistability (metabistability) predicted occur large lapse before reaching fully aligned state. Finally, computed values favorably compare available experimental data.