Due to growing importance of study of bio-fluids in rotational microfluidic platforms, discussion of flow of viscoplastic materials in such situations becomes very important. Bio-fluids also generally flow in soft channel microfluidic environment and therefore studying the effect of softness of channels on flow of such viscoplastic bio-fluids becomes critical. We, in the present study, investigate the effect of the rotation of the channel and yield stress of the fluid on the flow of viscoplastic material in a soft microchannel for three constitutive models viz. Bingham, Casson and Herschel–Bulkley models. It is found that the soft grafted layer, the channel rotation and the fluid yield stress play vital roles in determining the flow behaviour. We find that that larger rotational speeds tend to destabilize the flow. We also find the critical rotational speed for which secondary flow magnitude is maximum. We also find that this non-linear interaction between rotation of channel and fluid yield stress leads to the generation of multiple yield planes within the flow domain. Our study will help in obtaining good designs of rotational microfluidic platforms for studying bio-fluids with yield stress.

由于在旋转微流体平台上研究生物流体的重要性越来越高，因此在这种情况下讨论粘塑性材料的流动变得非常重要。生物流体通常也在软通道微流体环境中流动，因此研究通道的柔软度对这种粘塑性生物流体的流动的影响变得至关重要。在本研究中，我们针对三个本构模型研究了通道旋转和流体屈服应力对软微通道中粘塑性材料流动的影响。Bingham，Casson和Herschel-Bulkley模型。发现软接枝层，通道旋转和流体屈服应力在决定流动特性方面起着至关重要的作用。我们发现较大的旋转速度容易使流量不稳定。我们还找到了次级流量最大的临界转速。我们还发现，通道旋转与流体屈服应力之间的这种非线性相互作用导致流域内多个屈服面的产生。我们的研究将有助于获得良好的旋转微流体平台设计，以研究具有屈服应力的生物流体。