Three-dimensional simulations of undulatory and amoeboid swimmers in viscoelastic fluids

Abstract

We explore swimming speeds of C. elegans and amoeboids in viscoelastic fluids with three-dimensional, large amplitude simulations.

Squirmers with swirl at low Weissenberg number

“…2011; Zhu, Lauga & Brandt 2012; Thomases & Guy 2014; Li et al. 2017; Binagia, Guido & Shaqfeh 2019) or enhancing (Teran, Fauci & Shelley 2010; Liu, Powers & Breuer 2011; Spagnolie, Liu & Powers 2013; Riley & Lauga 2014; Thomases & Guy 2014, 2017; Patteson et al. 2015; Binagia et al.…”

“…Notably, these biofluids are often viscoelastic, meaning they exhibit both a fluid-like and solid-like response to deformation (D'Avino & Maffettone 2015). This fluid elasticity can have a profound impact on the motility of swimming micro-organisms, either hindering (Fu, Powers & Wolgemuth 2007;Lauga 2007;Fu, Wolgemuth & Powers 2009;Shen & Arratia 2011;Zhu et al 2011;Zhu, Lauga & Brandt 2012;Thomases & Guy 2014;Li et al 2017;Binagia, Guido & Shaqfeh 2019) or enhancing (Teran, Fauci & Shelley 2010;Liu, Powers & Breuer 2011;Spagnolie, Liu & Powers 2013;Riley & Lauga 2014;Thomases & Guy 2014, 2017Patteson et al 2015;Binagia et al 2020) propulsion depending upon the swimmer's gait, the structural properties of the immersed body and, of course, the rheology of the fluid (Dasgupta et al 2013). Likewise, in regard to collective motion, viscoelasticity has been shown to have a substantial effect, engendering both aggregation and alignment of swimming cells (Li & Ardekani 2016;Tung et al 2017;Ishimoto & Gaffney 2018).…”

Swimming with swirl in a viscoelastic fluid

“…In many cases, it has been observed that fluid elasticity can lead to a decrease in the swimming speed (Fu, Powers & Wolgemuth 2007; Lauga 2007; Fu, Wolgemuth & Powers 2009; Shen & Arratia 2011; Zhu etal. 2011; Zhu, Lauga & Brandt 2012; Binagia, Guido & Shaqfeh 2019). One may then ask under what conditions can elasticity actually enhance the speed of a swimming microorganism?…”

On the rheology of particle suspensions in viscoelastic fluids

“…Simulation of undulatory swimming in viscoelastic fluids. (Left) Undulatory swimming of Chlamydomonas reinhardtii in an aqueous polymer solution showing the strain energy (trace of the elastic stress tensor), and (right) undulatory swimming of Chlamydomonas elegans in a similar solution with comparable contours of the trace of the elastic stress tensor . Note in both cases, the concentration of stress energy near the head/tail of the undulating bodies…”

“…However, there is little understanding of the rheology of swimming suspensions in elastic fluids for reasons similar to the dearth of understanding of passive particle suspensions in elastic fluids. Moreover, the effect of elasticity on single particle swimming motion has only been examined in detail in three dimensions for the ciliated motion of Chlamydamonas and, more recently for Caenorhabditis elegans and amoeboid swimming (cf. Figure ).…”