Meeting Abstract
Seals use their highly sensitive whiskers to track the hydrodynamic trails of their swimming prey. These whiskers have a unique undulated surface geometry that affects water flow over the structure and influences vortex shedding. Whisker geometry varies between species but the effect of these morphology variations is unknown. By creating whisker models with dramatically modified features, we are able to isolate the effects of specific geometric parameters. Models were tested both computationally and experimentally. For computational fluid dynamics (CDF) simulations, sixteen digital models were generated that isolated seven non-dimensional parameters including undulation wavelength, thickness, slenderness, amplitudes in the streamwise and transverse flow directions, as well as a peak-shift and a symmetry parameter that induce a non-sinusoidal periodic undulation. CFD simulations produced a ranked list of important features that are most influential for reducing drag, root-mean-square lift force, and shifting the frequency spectra. Of these, wavelength was revealed as an important feature. Four physical models (with wavelength as the only variant) were 3D printed and tested in a water tunnel using dye visualization, at the biologically relevant Reynolds number range of 250-800. Flow visualization demonstrated the ability of the undulations to enhance the spanwise momentum transport, reduce the recirculation region, and modify the frequency spectra in the recirculation region behind the whisker.
