Modelling deformable particles in complex fluid flow: A reduced-order modelling approach

Description

Deformable particles are of particular interest in many complex multiphase flows including blood flow, where biological cells (e.g. red blood cells) deform and exhibit particular behaviour such as migration towards the centre of the blood vessel. Mathematical modelling of deformable particles in interaction with the fluid flow is cumbersome due to the high computational costs as well as the level of complexity involved in coupling the physics of particle and fluid. In this study, a reduced-order model for deformable particles is proposed and implemented within the framework of resolved CFD-DEM. The deformable particle is modelled as a clump of spheres inter-connected by means of virtual elastic bonds. Each bond behaves similar to a cantilever beam with the possibility to translate and rotate along with the spheres and is implemented in the frame of C++ libraries of LIGGGHTS for flexible fibres. We further extended this flexible bond model in order to generate a ring-shaped deformable particle out of overlapping constituent spheres. The present work focuses on red blood cells and the model parameters are calibrated based on the force-displacement curves. Static calibration performed shows that the model is capable of reproducing good static mechanics of RBC. Additionally, from dynamic calibration, the creep behaviour of RBC is also captured by the present model. Our model was coupled with the immersed boundary solver in CFDEM coupling software and preliminary results show good agreement with literature in tube flows. Further modifications and improvements will be made to the solver and validated for multiple red blood cell systems.

Period	09 Apr 2019
Event title	PARTEC2019 - International Congress on Particle Technology
Event type	Conference
Location	GermanyShow on map