Influence of viscous boundary layer on wave propagation on isolated tectorial membranes

Abstract

The tectorial membrane is an extracellular matrix located in the cochlea. The tectorial membrane is often hypothesized to play an important role in hearing mechanics. Measurements of wave propagation on isolated tectorial membranes have been used in the literature to characterize the intrinsic mechanical properties of tectorial membranes in the auditory frequency range. While most previous studies have made an implicit assumption regarding the width of the tectorial membranes in order to find the properties of the TM using a simple model, we have recently used a more accurate model that takes into account the finite width of the TM and its anisotropy. However, experiments are conducted in an artificial endolymph bath, which we neglected in our previous analysis. In this work, we study the influence of the viscous boundary layer due to the fluid on wave propagation on isolated tectorial membranes. The boundary layer adds damping and mass to the tectorial membrane, which we model using a commercial finite element software. The influence of the boundary layer on the space constant and wave speed of the longitudinally propagating radial motion, and on the spatial patterns of the longitudinal motion, are analyzed.