{"id":345729,"date":"2016-12-29T03:00:00","date_gmt":"2016-12-29T00:00:00","guid":{"rendered":"http:\/\/www.fyysika.ee\/?guid=7d2cf6afc182d870ccdb7700ad005812"},"modified":"2016-12-29T03:00:00","modified_gmt":"2016-12-29T00:00:00","slug":"lift-crisis-of-a-spinning-table-tennis-ball","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=345729","title":{"rendered":"Lift crisis of a spinning table tennis ball"},"content":{"rendered":"<p>The aerodynamic properties of a spinning table tennis ball were investigated using flight<br \/>\nexperiments. Using high-speed video cameras, the trajectory and rotation of an official ball<br \/>\n(Nittaku 3-Star Premium), which was launched by a three rotor machine, were recorded. The drag and<br \/>\nlift coefficients ( C D and C L ) were determined by analysing the video images. The measurements<br \/>\ncovered the speed and rotation range of typical table tennis shots in the form of the Reynolds<br \/>\nnumber ( Re ) and dimensionless spin rate ( SP ), i.e. 3.0\u00a0\u00d7\u00a010 4\u00a0<\u00a0Re\u00a0<\u00a09.0\u00a0\u00d7\u00a010 4 and0\u00a0<\u00a0SP\n\u00a0<\u00a01.0, and C D and C L were obtained as functions of Re and SP . We determined that the lift\ncoefficient C L is not a monotonically increasing function of SP . A deep valley of C L was found\naround SP\u00a0=\u00a00.5, and the lift force exerted ...\n<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The aerodynamic properties of a spinning table tennis ball were investigated using flight<br \/>\nexperiments. Using high-speed video cameras, the trajectory and rotation of an official ball<br \/>\n(Nittaku 3-Star Premium), which was launched by a three rotor machine, were recorded. The drag and<br \/>\nlift coefficients ( C D and C L ) were determined by analysing the video images. The measurements<br \/>\ncovered the speed and rotation range of typical table tennis shots in the form of the Reynolds<br \/>\nnumber ( Re ) and dimensionless spin rate ( SP ), i.e. 3.0\u00a0\u00d7\u00a010 4\u00a0&lt;\u00a0Re\u00a0&lt;\u00a09.0\u00a0\u00d7\u00a010 4 and0\u00a0&lt;\u00a0SP<br \/>\n\u00a0&lt;\u00a01.0, and C D and C L were obtained as functions of Re and SP . We determined that the lift<br \/>\ncoefficient C L is not a monotonically increasing function of SP . A deep valley of C L was found<br \/>\naround SP\u00a0=\u00a00.5, and the lift force exerted &#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[178],"tags":[],"class_list":{"0":"post-345729","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-rss-fuusikaharidus","7":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/345729","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=345729"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/345729\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=345729"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=345729"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=345729"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}