Passive wake detection using seal whisker-inspired sensing
Beem, Heather R.
MetadataShow full item record
This thesis is motivated by biological experiments, which display the harbor seal's ability to track the wake of an object several seconds after it swam by. In this work, I elucidate the basic fluid mechanisms that seals may employ to accomplish this detection. Key are the unique vortex-induced vibration (VIV) properties resulting from the geometry of the harbor seal whisker. First, force measurements and flow visualizations on a rigid whisker model undergoing 1-D imposed oscillations show that the geometry passively reduces VIV (factor of >10), despite contributions from effective added mass and damping. This suggests that harbor seal whiskers would detect details of the oncoming flow with reduced background “noise". Next, a biomimetic whisker sensor is designed by mounting the model on a four-armed flexure, allowing it to freely vibrate, and using strain gauges to measure deflections at the whisker base. Finally, this whisker device is towed behind an upstream cylinder with larger diameter. In the wake, the whisker oscillates with large amplitude and at the Strouhal frequency of the upstream cylinder. A slaloming motion among the wake vortices drives this interaction, and it enables detection of the upstream wake.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2015
Showing items related by title, author, creator and subject.
Experimental and seismological constraints on the rheology, evolution, and alteration of the lithosphere at oceanic spreading centers deMartin, Brian J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-02)Oceanic spreading centers are sites of magmatic, tectonic, and hydrothermal processes. In this thesis I present experimental and seismological constraints on the evolution of these complex regions of focused crustal ...
Caron, David A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1984-06)The distribution and feeding behavior of bacterivorous micro flagellates (2-20 μm protozoa) and their ingestion by copepods were examined in an attempt to assess the importance of these protozoa as a trophic link ...
Henrichs, Susan M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1980-08)Dissolved free amino acids (DFAA) were measured in interstitial water samples squeezed from sediments collected in a variety of depositional environments. These sediments were further characterized by measurements of ...