Multi-scale computational modeling of particle adhesion dynamics under shear flow

Abstract

Challenging questions exist in the understanding of particulate adhesion process in biological and industrial flows since these problems require modeling a wide range of spatiotemporal scales. The thesis is focused on multiscale modeling of particle adhesion process in shear flow with broad applications to practical suspension flow problems. The capabilities of this model were demonstrated by application to two different problems. In the application of thrombus simulation, a physical description of the von Willebrand factor (VWF) mediated thrombus growth process was formulated. The physics-based model captures distinct stages of the thrombus growth process in shear-induced platelet adhesion (SIPA) and platelet-aggregate morphology. It describes platelets dynamics, VWF dynamics, shear-dependent VWF domain activation, and VWF-platelet binding interactions under complex flow conditions. The model is useful in studying blood diseases like thrombotic microangiopathies (TMAs). By modeling interactions between VWF and platelets under physiological shear conditions, a stable web-like scaffold was formed, resulting in a complex network of cross-linked VWF and platelets that may contribute to microvascular obstruction. The results provide additional biophysical insight into the pathophysiology of TMAs. Another application is crystal formation and adhesion to surfaces in shear flow. A similar particle adhesion model framework was applied to study the scale induction when crystal fouling begins. Crystals adhere faster at lower wall shear rate and lower viscosity conditions. Also, crystals tend to form on top of the existing nucleus, forming 3D structures as compared to uniform adhesion on smooth surfaces.