Cilia-generated pumping of smart magneto-viscoplastic fluids under an oblique magnetic field : a model for smart soft robotic internal propulsion

Beg, OA; Beg, TA; Kadir, A; Theodoris, T; Gorla, R; Malysheva, LI; Kuharat, S

Abstract

Bio-inspired internal propulsion systems are increasingly emerging in soft robotics. These feature many complex “smart” working fluids which respond to external stimuli including electrical and magnetic fields. Internal walls may also feature artificially engineered cilia surfaces. Motivated by these applications, in the present work we investigate the cilia-generated internal propulsion of a magneto-viscoplastic actuator fluid in a two-dimensional micro-channel. The Casson model is implemented to simulate viscoplastic behavior of fluids. An external magnetic field is applied which is oblique to the fluid flow direction. Viscous dissipation effects are included. The flow is controlled by the metachronal wave propagation generated by cilia beating on the inner walls of the channel. The mathematical formulation is based on deformation in longitudinal and transverse velocity components induced by the ciliary beating phenomenon with the cilia assumed to follow elliptic trajectories. The model also features velocity and thermal slip boundary conditions. Closed-form solutions to the non-dimensional boundary value problem are obtained under physiological limitations of low Reynolds number and large wavelength. The influence of key hydrodynamic and thermo-physical parameters i.e. Hartmann (magnetic) number, Casson (viscoplastic) fluid parameter, thermal slip parameter and velocity slip parameter on flow characteristics are investigated. A comparative study is also made with Newtonian fluids (corresponding to massive values of plastic viscosity). Streamlines are plotted to visualize trapping phenomenon. The computations reveal that velocity increases with increasing the magnitude of Hartmann number near the channel walls whereas in the core flow region (centre of the channel) significant deceleration is observed. Temperature is elevated with greater Casson parameter, Hartmann number, velocity slip, eccentricity parameter, thermal slip and also Brinkmann (dissipation) number. Furthermore, greater Casson parameter is found to elevate the quantity and size of the trapped bolus. In the pumping region, the pressure rise is reduced with greater Hartmann number, velocity slip, and wave number whereas it is enhanced with greater cilia length. The simulations provide a first step in probing more deeply into the fluid dynamic mechanisms of ciliated and magnetically actuated soft robotic conduits.

Citation

Beg, O., Beg, T., Kadir, A., Theodoris, T., Gorla, R., Malysheva, L., & Kuharat, S. Cilia-generated pumping of smart magneto-viscoplastic fluids under an oblique magnetic field : a model for smart soft robotic internal propulsion. Presented at ICAMAME 2022: 16th International Conference on Aerospace, Mechanical, Automotive and Materials Engineering, Cancun, Mexico

• Presentation Conference Type: Other
• Conference Name: ICAMAME 2022: 16th International Conference on Aerospace, Mechanical, Automotive and Materials Engineering
• Conference Location: Cancun, Mexico
• End Date: Apr 6, 2022
• Acceptance Date: Dec 13, 2020
• Deposit Date: Jan 8, 2021
• Publisher URL: https://waset.org/aerospace-mechanical-automotive-and-materials-engineering-conference-in-april-2022-in-cancun
• Related Public URLs: https://waset.org/
• Additional Information: Event Type : Conference