%0 Journal Article %1 jibuti2014 %A Jibuti, Levan %A Zimmermann, Walter %A Rafaï, Salima %A Peyla, Philippe %D 2014 %K myown %T Effective viscosity of active suspensions: Three-dimensional numerical modeling %U http://arxiv.org/abs/1412.3176 %X A three-dimensional model is proposed for Chlamydomonas Reinhardtii swimming with a breaststroke-like beating of its two flagella. The model reveals unusual angular orbits of the active swimmer under a linear shear flow. Namely, the swimmer sustains orientation transiently across the flow when flagella plane is perpendicular to the shear plane, and amplify the shear-induced rotation along the flow. Such behavior is a result of the interplay between shear-induced deformation and swimmer's periodic beating motion that exerts internal torques on the torque-free swimmer. This particular behavior has some significant consequences on the rheological properties of the suspension that tends to confirm previous experimental results Phys. Rev. Lett. 104, 098102 (2010). We calculated the intrinsic viscosity of the suspension with such isolated modeled microswimmers (dilute case) in shear flow using numerical simulations based on Rotne-Prager approximation. The results show an increased intrinsic viscosity for active swimmer suspensions in comparison to non-active ones in accordance with previous experimental measurements. A major enhancement of the active swimmer viscosity occurs due to the effectively extended shape of the deformable swimming cells. We also recover the experimentally observed shear thinning behavior.

@article{jibuti2014, abstract = {A three-dimensional model is proposed for Chlamydomonas Reinhardtii swimming with a breaststroke-like beating of its two flagella. The model reveals unusual angular orbits of the active swimmer under a linear shear flow. Namely, the swimmer sustains orientation transiently across the flow when flagella plane is perpendicular to the shear plane, and amplify the shear-induced rotation along the flow. Such behavior is a result of the interplay between shear-induced deformation and swimmer's periodic beating motion that exerts internal torques on the torque-free swimmer. This particular behavior has some significant consequences on the rheological properties of the suspension that tends to confirm previous experimental results [Phys. Rev. Lett. 104, 098102 (2010)]. We calculated the intrinsic viscosity of the suspension with such isolated modeled microswimmers (dilute case) in shear flow using numerical simulations based on Rotne-Prager approximation. The results show an increased intrinsic viscosity for active swimmer suspensions in comparison to non-active ones in accordance with previous experimental measurements. A major enhancement of the active swimmer viscosity occurs due to the effectively extended shape of the deformable swimming cells. We also recover the experimentally observed shear thinning behavior.}, added-at = {2014-12-11T12:56:35.000+0100}, author = {Jibuti, Levan and Zimmermann, Walter and Rafaï, Salima and Peyla, Philippe}, biburl = {https://www.bibsonomy.org/bibtex/2d23c3095fb76e9a314fad1958e9b2be2/levan}, description = {Effective viscosity of active suspensions: Three-dimensional numerical modeling}, interhash = {80f0d40ffac335c42380631e9e13b303}, intrahash = {d23c3095fb76e9a314fad1958e9b2be2}, keywords = {myown}, note = {cite arxiv:1412.3176Comment: 8 pages, 6 figures}, timestamp = {2014-12-11T12:56:35.000+0100}, title = {Effective viscosity of active suspensions: Three-dimensional numerical modeling}, url = {http://arxiv.org/abs/1412.3176}, year = 2014 }