Tumbling, stretching and cross-stream migration of polymers in rectilinear shear flow from dissipative particle dynamics simulations

摘要: Abstract Solutions of flexible polymer chains with harmonic bonds undergoing rectilinear flow in slit pores are investigated via dissipative particle dynamics (DPD) simulations. We found that when DPD low Schmidt number ( Sc ∼ 1 ) is used, the tend to migrate across streamlines towards walls. However, a cross-stream migration centerline observed relatively high values 10 used. The effect chain length and Weissenberg number, defined as Wi = Γ τ rel , where shear rate longest relaxation time, respectively, investigated. exhibit large orientational extensional fluctuations, distributions both latitude azimuthal angles exhibiting power-law decays agreement experiments, theory previous tumbling kinetics characterized by an exponential distribution times. characteristic time scale proportional at equilibrium. power spectral density extension, while monotonically decaying for or exhibits shallow peak short chains, implying induces nearly repetitive chains. corresponding extension also time.