Research Activities

Analysis of resolved particles motion in a viscous fluid

Image Immersed Boundary
Velocity field for drafting, kissing, and tumbling of two falling spheres.

Abstract

Results of previous studies have shown that the rheological behavior of suspensions is a function of the particles’ motion characteristics. These motion characteristics could be simulated by CFD-DEM simulations. Collision force, long-range, and short-range hydrodynamic interactions are the three forces faced by particles in suspensions. General CFD-DEM simulations use a drag law assumption to calculate a hydrodynamic force faced by a particle, and they add a lubrication correction force in short gaps between particles.

The main aim of the present project is to directly calculate hydrodynamic forces from the CFD field without adding a lubrication correction term. For this reason, a variant of the immersed boundary method is developed and coupled with XDEM code to achieve this purpose. Different developments have been conducted on the code to increase its accuracy in capturing the hydrodynamics interactions. These improvements could be summarized as follow:

• Treating CFD cells between particles.

• Implementing a second-order interpolation scheme.

• Finding the relationship between mesh resolution and time step size on the accuracy of lubrication force.

To ensure the accuracy of the developed model, the code was validated with different reference work. For instance, IBM-XDEM model could capture the well-known phenomenon of drafting, kissing, and tumbling of two falling spheres. Since this project is a collaborative work with SPP2005, the developed IBM-XDEM code will simulate the rheological behavior of a suspension in the later part of this work.

People

Funding

This project was Founded by Luxembourg National Research Found (INTER/DFG/20/14843353 - ConMicMac).

Publications

Presented as an abstract at a conference entitled “From Stokesian suspension dynamics to particulate Flows in turbulence on 30th August in Toulouse”