Propulsion of an elastic filament in a shear-thinning fluid

Abstract

Some micro-organisms and artificial micro-swimmers propel at low Reynolds numbers (Re) via the interaction of their flexible appendages with the surrounding fluid. While their locomotion have been extensively studied with...

Enhanced clamshell swimming with asymmetric beating at low Reynolds number

“…There, clamshell swimmers can evade the scallop theorem by using timeasymmetric strokes 51,52 and non-Newtonian rheology can interact variably with body elasticity. 53…”

Elastohydrodynamic propulsion of a filament magnetically driven at both ends

“…To model the fluid-structure interaction, we consider a framework based on a multi-link discretization of the elastic filament. 41,[49][50][51] The filament is discretized by a chain of N rigid links of equal length c = L/N, which are serially connected by N À 1 torsional springs with a spring constant k. For the i-th link, the position vector of its left end is denoted as x i = x i e x + y i e y . The unit tangent and normal vectors of the link are denoted, respectively, as t i = cos y i e x + sin y i e y and n i = e z  t i , where y i is the angle between the tangent vector t i and the unit basis vector e x .…”

“…To actuate the filament magnetically, we impose a typical spatially uniform external magnetic field B = be x + b sin ote y considered in previous studies: 17,32,41,52,53 the field consists of a homogeneous static component of strength b in the x-direction and a sinusoidally oscillating field of amplitude b and frequency o in the y-direction. The resulting magnetic field B thus oscillates around the x-axis by AE451, with a magnitude that varies between b and ffiffi ffi 2 p b.…”

“…These general characteristics of elastohydrodynamic propulsion with end actuation are well characterized in terms of relevant dimensionless groups (see more details in Sections 2 and 3 below). Other studies have also examined how variable bending stiffness, 35,36 intrinsic curvature, 37,38 non-Newtonian rheology, [39][40][41][42] and interactions of multiple filaments [43][44][45] impact the propulsion performance of flexible microswimmers.…”

Autonomously Propelled Colloids for Penetration and Payload Delivery in Complex Extracellular Matrices

“…A growing body of evidence indicates that ECM viscoelasticity influences fundamental cell processes such as differentiation, spreading, migration, and ECM synthesis, and plays a key role in the procession of diseases such as fibrosis and cancer [ 49 ]. Considering the growing body of literature on microscale self-propulsion in shear-thinning [ 113 , 114 , 115 ] and viscoelastic media [ 116 , 117 ], it is reasonable to expect that ECM viscoelasticity will influence the efficiency of the self-propulsion. Accordingly, to develop SPPs that are attractive for biomedical applications in drug delivery in human tissues, it is critical that the swimming performance of SPPs be tested in environments that possess similar viscoelastic characteristics to in vivo human tissues.…”