{"id":413212,"date":"2017-05-25T02:00:00","date_gmt":"2017-05-24T23:00:00","guid":{"rendered":"http:\/\/www.fyysika.ee\/?guid=dbb7284cdf971ded89ce9cd835d89c30"},"modified":"2017-05-25T02:00:00","modified_gmt":"2017-05-24T23:00:00","slug":"creating-drag-and-lift-curves-from-soccer-trajectories","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=413212","title":{"rendered":"Creating drag and lift curves from soccer trajectories"},"content":{"rendered":"<p>Trajectory analysis is an alternative to using wind tunnels to measure a soccer ball\u2019s aerodynamic<br \/>\nproperties. It has advantages over wind tunnel testing such as being more representative of game<br \/>\nplay. However, previous work has not presented a method that produces complete, speed-dependent drag<br \/>\nand lift coefficients. Four high-speed cameras in stereo-calibrated pairs were used to measure the<br \/>\nspatial co-ordinates for 29 separate soccer trajectories. Those trajectories span a range of launch<br \/>\nspeeds from 9.3 to 29.9 m s \u22121 . That range encompasses low-speed laminar flow of air over a soccer<br \/>\nball, through the drag crises where air flow is both laminar and turbulent, and up to high-speed<br \/>\nturbulent air flow. Results from trajectory analysis were combined to give speed-dependent drag and<br \/>\nlift coefficient curves for the entire range of speeds found in the 29 trajectories. The average<br \/>\nroot mean square error between the measured and modelled trajectory was 0.028 m horizontally a&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Trajectory analysis is an alternative to using wind tunnels to measure a soccer ball\u2019s aerodynamic<br \/>\nproperties. It has advantages over wind tunnel testing such as being more representative of game<br \/>\nplay. However, previous work has not presented a met&#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-413212","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\/413212","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=413212"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/413212\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=413212"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=413212"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=413212"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}