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We present an experimental study on the shear‐induced migration and axial development of particles in the channel flows of non‐Brownian suspensions. The suspending fluid is Newtonian. We investigate fracturing flows with a Hele‐Shaw type scaling through building a unique channel setup and an advanced optical system. The local particle concentration profiles are measured via the refractive‐index matching technique for a wide range of bulk volume fraction, that is, 0.1≤ϕ¯b≤0.5. Simultaneously, the particle image velocimetry is performed to determine the velocity profile of the particle phase. We compare our experimental results with the available two‐phase continuum frameworks and show discrepancies and similarities in the fully developed and axial development of the solid volume fraction profiles. We discuss directions in which the continuum frameworks require improvements. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a three‐dimensional numerical solver is developed for suspensions of rigid and soft particles and droplets in viscoelastic and elastoviscoplastic (EVP) fluids. The presented algorithm is designed to allow for the first time three‐dimensional simulations of inertial and turbulent EVP fluids with a large number particles and droplets. This is achieved by combining fast and highly scalable methods such as an FFT‐based pressure solver, with the evolution equation for non‐Newtonian (including EVP) stresses. In this flexible computational framework, the fluid can be modeled by either Oldroyd‐B, neo‐Hookean, FENE‐P, or Saramito EVP models, and the additional equations for the non‐Newtonian stresses are fully coupled with the flow. The rigid particles are discretized on a moving Lagrangian grid, whereas the flow equations are solved on a fixed Eulerian grid. The solid particles are represented by an immersed boundary method with a computationally efficient direct forcing method, allowing simulations of a large numbers of particles. The immersed boundary force is computed at the particle surface and then included in the momentum equations as a body force. The droplets and soft particles on the other hand are simulated in a fully Eulerian framework, the former with a level‐set method to capture the moving interface and the latter with an indicator function. The solver is first validated for various benchmark single‐phase and two‐phase EVP flow problems through comparison with data from the literature. Finally, we present new results on the dynamics of a buoyancy‐driven drop in an EVP fluid. We develop an efficient solver for the direct numerical simulations of viscoelastic and elastoviscoplastic multiphase flows. The solver is validated for various benchmark single‐phase and two‐phase elastoviscoplastic flow problems. We study a Newtonian droplet rising in an elastoviscoplastic fluid and show the appearance of a negative wake. [ABSTRACT FROM AUTHOR]

The cover image is based on the Research Article Computational modeling of multiphase viscoelastic and elastoviscoplastic flows, by Daulet Izbassarov et al., https://doi.org/10.1002/fld.4678. [ABSTRACT FROM AUTHOR]