BPCPPDYSOE21 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Complex Fluids and Soft Matter 3 (joint session DY/CPP)

CPP 13.5: Vortrag

Dienstag, 23. März 2021, 15:50–16:10, DYc

Hydrodynamics of immiscible binary fluids with viscosity contrast: A Multiparticle Collision Dynamics approach — •Zihan Tan¹, Vania Calandrini², Jan Dhont¹, Gerhard Nägele¹, and Roland Winkler³ — ¹Biomacromolecular Systems and Processes, Institute of Biological Information Processing, Forschungszentrum Jülich, 52428 Jülich, Germany — ²Computational Biomedicine, Institute for Advanced Simulation, Forschungszentrum Jülich, 52428 Jülich, Germany — ³Theoretical Physics of Living Matter, Institute for Advanced Simulation, Forschungszentrum Jülich, 52428 Jülich, Germany

By coupling distinct collision steps in each fluid domain, immiscible binary fluids with different viscosities connected by coarse-grained planer interfaces are realized by multiparticle collision dynamics (MPC). The flow and the stress-viscosity relation of the system are investigated under shear flow, excellently agree with continuum hydrodynamics solution and the analytical theory of MPC. Later, the hydrodynamic mobility coefficients of an embedded colloid close to the fluid-fluid interface are measured, which coincide with hydrodynamic multipole expansion calculations. To validate the length and time scales of hydrodynamics in this model, we explore the corresponding transverse velocity correlations. It is found that the correlations for the fluid regions occupied by one phase are identical to single-phase MPC fluid. In contrast, the transverse modes at the interfacial region can be interpreted by the superposition of both viscous components.