(a) A photograph of the PAV; (b) longitudinal cut of the PAV (left-hand side) and transverse cut (right-hand side) of the tube containing the piezoelements. Reproduced from Crassous et al., Journal of Rheology 49, 851–863 (2005).
Dynamic strain sweep measurement on different concentrations of S. obliquus algae suspension at constant frequency of 10 rad/s using the ARES. G′ data (empty symbol) and G″ data (full symbol). Cell concentrations of 15 vol. % (), 9.0 vol. % (), and 6.8 vol. % ().
Validation experiment on the PAV data with the ARES data for a 9 vol. % S. obliquus suspension. ARES data (empty symbol) and PAV data with a gap size of 25 μm (full symbol). η* (), G″ (), and G′ ().
Variation of complex viscosity with volume fraction at different frequencies of 49 Hz (), 95 Hz (), and 241 Hz () obtained using PAV at 25 °C. A linear straight line shows the Einstein prediction.
Dependence of storage modulus (G′) on volume fraction at different frequencies of 49 Hz (), 95 Hz (), and 241 Hz () from PAV measurements at 25 °C.
Dependence of loss modulus (G″) on volume fraction at different frequencies of 49 Hz (), 95 Hz (), and 241 Hz () from PAV measurements at 25 °C.
A plot of the phase angle (θ) as a function of volume fraction at a frequency of 241 Hz using the PAV at 25 °C. The graph shows that at low concentration, θ is closer to the theoretical 90° for Newtonian fluids.
Cox–Merz plot showing apparent viscosity from ARES steady shear () and complex viscosity from ARES dynamic frequency sweeps () and PAV frequency sweeps with a gap size of 35 μm () on a 12 vol. % S. obliquus suspension at 25 °C.
Optical micrographs of 0.2 vol. % S. obliquus algae suspension taken with an Olympus BH-2 at 50× magnification during shearing (a) no shear, (b)–(d) with shear rate of 10 s−1, 100 s−1, and 1000 s−1, respectively, after 20 s.
Effect of motility on LVE response for a 3 vol. % S. obliquus algae suspension from PAV measurement with a gap size of 10 μm. (a) Storage modulus, G′ (b) loss modulus, G″ and (c) complex viscosity, η*.
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