HYDRODYNAMICS OF METACHRONAL ROWING AT INTERMEDIATE REYNOLDS NUMBERS

Metachronous rowing is a swimming mechanism widely adopted by small marine invertebrate like comb jellies, in which rows of appendages perform propulsive strokes sequentially in a coordinated manner with a fixed phase difference. To simulate metachronous rowing at intermediate Reynolds number, in this paper, a row of flexible cilia models was placed inside the flow field, with their roots stroke at a sinusoidal function of time and a fixed phase difference. A fully coupled two-way numerical solver was developed, which solves the Navier- Stokes equations for the fluid field coupled with the differential equation for the flexible cilia model. This numerical solver is applied to investigate how the row of cilia models are deformed by the hydrodynamic forces (pressure and shear) and momentum and thus impact hydrodynamic performance. Results show that the passive deformation of cilia potentially improve the hydrodynamic performance compared to the rigid cilia. With the metachronous rowing mechanism, the cilia generate the thrust to move forward. The approach used in this study presents a general way to explore the fluid dynamics of complex fluid-structure interaction problems.