Lift and Drag Forces for a Sphere on a Flat Wall in Non-Newtonian Shear Flow

Yaroslav Ignatenko,Roland May,Oleg Bocharov,D Markovich,A Semenov,D Zaitsev

doi:10.1051/epjconf/201715900014

Yaroslav Ignatenko, Roland May + Show 4 more

Open Access

https://doi.org/10.1051/epjconf/201715900014

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Abstract

Parametrical study of perfect steady rolling and steady state freely motion of spherical particle on the wall in shear flow of non-Newtonian fluid was carried out. In the case of perfect rolling the jumps of forces acting on a sphere in the moment of changing particle velocity from zero to positive were observed. Non-Newtonian properties of fluid lead to decreasing of drag force coefficient for low particle's velocity and to opposite effect for high velocity relative to Newtonian fluid. There is no such significant effect for a lift force coefficient. Steady state particle's velocity (Fd (Vpss )=0) increases for non-Newtonian fluid for both considered types of motion. Steady state particle's velocity and lift force coefficient are lower for the case of freely particle motion. Steady state rotational velocity decreases for non-Newtonian fluid.

Highlights

One of multiphase flow regimes is stirring or lifting of particles over a wall or a bed of particles
We considered two cases – perfect rolling and freely motion
The simulation investigated the forces acting on the sphere and their dependence upon the flow regime and fluid rheology properties while a perfect rolling of a sphere on the wall

Summary

Introduction

One of multiphase flow regimes is stirring or lifting of particles over a wall or a bed of particles. The movement of river drift and the transport of cuttings during horizontal drilling can be described by this simple model In these situations, the determination of forces acting on the particle is an important and fundamental task. Two scenarios were considered: a resting sphere in shear flow and a moving sphere in a non-moving fluid In the latter scenario, the drag force and torque increases logarithmically with decreasing wall distance. Sphere motion on the wall was investigated numerically by Lee et al [3, 4] using Navier-Stokes equations. They considered perfect rolling and free motion with creeping for a Newtonian fluid. Current study is concentrated on effect of non-Newtonian fluid rheology for the problem of single particle motion on a wall

Problem statements

Results and Discussion

Perfect rolling

Freely motion