Mathematics

The modeling of the beating of cilia and flagella in fluids is a particularly active field of study, given the biological relevance of these organelles. Various mathematical models have been proposed to represent the nonlinear dynamics of flagella, whose motion is powered by the work of molecular motors attached to filaments composing the axoneme. Here, we formulate and solve a nonlinear model of activation based on the sliding feedback mechanism, capturing the chemical and configurational changes of molecular motors driving axonemal motion. This multiscale model bridges microscopic motor dynamics with macroscopic flagellar motion, providing insight into the emergence of oscillatory beating. We validate the framework through linear stability analysis and fully nonlinear numerical simulations, showing the onset of spontaneous oscillations. To make the analysis more comprehensive, we compare our approach with two established sliding feedback models.