The semicircular canals, composed of lateral, anterior and posterior canals in the inner ear, are the sensors of equilibrium during head rotation movements in the three-dimensional space. Semicircular canals are filled with endolymph confined by the cupula. The study of the relationship between endolymph flow and cupular deformation is important in revealing the semicircular canals biomechanical behavior. To date, there are few studies focusing on the transient endolymph flow and cupular deformation in response to a head rotation motion. The lateral semicircular canal is mainly responsible for the sense of the horizontal rotation movement. In order to figure out the intricate dynamics in the lateral semicircular canal during the head rotation motion, the time evolutions of both endolymph flow and cupular deformation are analyzed in this article by using a fully coupled fluid-structure interaction model. It is shown that the cupular deformation provides cues for understanding the physiology of sensing the head rotation.
The cochlea is an important structure in the hearing system of humanity. Its unique structure enables the sensibility to the sound waves of varied frequencies. The widely accepted model of the cochlea is expressed as a long tube longitudinally divided by a membrane named the Basilar Membrane (BM), into two fluid-filled channels. Based on various assumptions for the cochlear fluid and structure, simplified mathematical and mechanical cochlear models were developed to help to understand the mechanism of the complex coupled system in the past decades. This paper proposes a hydrodynamic numerical cochlear model with consideration of the Fluid-Structure Interaction (FSI). In this model, the cochlear lymph is considered as in a Newtonian viscous fluid, and the basilar membrane is modeled as a composite structure. The traveling wave is simulated. Also focusing on the pressure in the fluid field, the results are compared with studies of Peterson and Bogert, where it was assumed that the slow compressive waves are traveling along the BM. Furthermore, the transmitting time of the cochlear traveling wave is also discussed.
