{"id":15217,"date":"2015-12-07T10:00:00","date_gmt":"2015-12-07T10:00:00","guid":{"rendered":"http:\/\/blog.journals.cambridge.org\/?p=15217"},"modified":"2015-12-11T11:20:08","modified_gmt":"2015-12-11T11:20:08","slug":"what-do-harbor-seals-and-downhill-skiers-have-in-common","status":"publish","type":"post","link":"https:\/\/www.cambridge.org\/core\/blog\/2015\/12\/07\/what-do-harbor-seals-and-downhill-skiers-have-in-common\/","title":{"rendered":"What do harbor seals and downhill skiers have in common?"},"content":{"rendered":"<div id=\"bsf_rt_marker\"><\/div><p>An unexpected similarity between nature\u2019s mechanisms and man\u2019s techniques arise in a new study published in\u00a0<em>Journal of Fluid Mechanics<\/em>. The paper reveals how harbor seals can detect prey from far away, and it\u2019s related to skiing.<\/p>\n<p>Around a decade ago, marine biologists began measuring the harbor seal\u2019s uncanny ability to track objects several seconds after they had swum by. The \u201cfootprints\u201d behind the object served as markers. Even if the seals were blindfolded, they could pick up on the markers by using their whiskers. What physical mechanism could be driving this phenomenon?<\/p>\n<p>Heather Beem, then-graduate student in Mechanical &amp; Oceanographic Engineering, and her PI, Prof. Michael Triantafyllou, designed a model experiment of a seal whisker encountering such \u201cfootprints\u201d. \u00a0In the MIT Towing Tank, she mounted a circular cylinder, which generated a vortex wake, similar to what a swimming fish creates in the water. She fabricated a plastic whisker-like sensor and towed it in the cylinder\u2019s wake.<\/p>\n<p>These experiments revealed an exquisite sensitivity of the whisker to detect the presence of the wake. As soon as the whisker hit the wake, it synchronized its motion to the periodic pattern of the swirling vortices. Flow visualizations displayed the whisker to slalom perfectly back-and-forth through the vortices, extracting energy to power large vibrations in the whisker. These wake-induced vibrations would clearly indicate to the seal that it was in the trail of the fish.<\/p>\n<p>Just as a racing skier zig-zags between gates, harbor seal whiskers slalom between vortices, leading the seal straight to the source of its dinner.<\/p>\n<p>MIT Mechanical Engineering\u2019s YouTube Channel:<\/p>\n<p><iframe loading=\"lazy\" width=\"1778\" height=\"1000\" src=\"https:\/\/www.youtube.com\/embed\/FE9U0b2fjOA?feature=oembed\" frameborder=\"0\" allowfullscreen><\/iframe><\/p>\n<p>This paper is freely available for 30 days via the following link: <a href=\"http:\/\/journals.cambridge.org\/flm\/beem\" target=\"_blank\">journals.cambridge.org\/flm\/beem<\/a><\/p>\n<p>Photo credit: Heather Beem<\/p>\n","protected":false},"excerpt":{"rendered":"<p>An unexpected similarity between nature\u2019s mechanisms and man\u2019s techniques arise in a new study published in the Journal of Fluid Mechanics. The paper reveals how harbor seals can detect prey from far away, and it\u2019s related to skiing.<\/p>\n","protected":false},"author":371,"featured_media":15221,"comment_status":"open","ping_status":"open","sticky":true,"template":"","format":"standard","meta":{"footnotes":""},"categories":[19,1,2254,9],"tags":[1716,1137,347,346,349],"coauthors":[],"class_list":["post-15217","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-life-sciences","category-news","category-physics","category-science-technology","tag-flow-visualizations","tag-fluid-dynamics","tag-fluid-mechanics","tag-jfm","tag-journal-of-fluid-mechanics"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/posts\/15217","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/users\/371"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/comments?post=15217"}],"version-history":[{"count":0,"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/posts\/15217\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/media\/15221"}],"wp:attachment":[{"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/media?parent=15217"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/categories?post=15217"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/tags?post=15217"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.cambridge.org\/core\/blog\/wp-json\/wp\/v2\/coauthors?post=15217"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}