Intrinsic Viscosity of Actively Swimming Microalgae Suspensions
Michael Johnston (UIUC), Lucas Caretta (U of MN), Randy Ewoldt (UIUC)
Hydrodynamics of Swimming Microorganisms
Tue 4:20 - 5:40
Barus-Holley 191
Suspensions of actively swimming microorganisms exhibit an effective viscosity which may depend on volume fraction, cell shape, and the nature of locomotion, e.g. pushers vs. pullers. Various theories have recently been developed to predict the effective viscosity of actively swimming suspensions; such theories typically neglect hydrodynamic interactions and therefore strictly apply only to the dilute concentration limit. Here we tests these dilute theories with experimental observations. We use a rotational rheometer to measure the dynamic shear viscosity for both motile and non-motile suspensions of D. Primolecta at concentrations ranging from 0.01% to 1% of volume fraction. With measurement precision within 0.5%, we are able to resolve the intrinsic viscosity and compare to current theories.