{"id":33,"date":"2018-08-09T13:16:29","date_gmt":"2018-08-09T13:16:29","guid":{"rendered":"http:\/\/commons.princeton.edu\/63-2-tiger-cub\/?p=33"},"modified":"2018-08-15T13:38:00","modified_gmt":"2018-08-15T13:38:00","slug":"notes-by-eric","status":"publish","type":"post","link":"https:\/\/commons.princeton.edu\/63-tiger-cub\/2018\/08\/09\/notes-by-eric\/","title":{"rendered":"27 February 2018"},"content":{"rendered":"<p>Notes by Eric: Professor Littman was not here today. In his absence, we were joined by a guest: Professor Luigi Martinelli<\/p>\n<ul>\n<li>Broad overview of the role of fluid mechanics, and more generally whatever happens when you try to move against air or water<\/li>\n<li>Whenever you are doing mundane tasks, you are dealing with fluid flows. Either they are opposing your motion or helping you.<\/li>\n<\/ul>\n<p>o Two regimes\u2014organized (laminar) and chaotic (turbulent)<\/p>\n<ul>\n<li>Chaotic flow will offer more resistance to the motorcycle<\/li>\n<li>Cost of turbulent flow vs. closing the wake is a tradeoff constantly considered.<\/li>\n<li>Distance between back of ride and wake seeks to be minimized.<\/li>\n<li>Some helmets are designed to minimize the gap between the rider and the air flow<\/li>\n<li>Often propulsion requires a working fluid<\/li>\n<\/ul>\n<p>o The flow rate\u2014the amount of fluid that can go in or out\u2014is determined by the shape of the valve.<\/p>\n<p>o The sizing of the fin is determined by the property of the flow of the engine head; therefore, the extent of the fin design of an air cool engine<\/p>\n<ul>\n<li>Sometimes the two combine<\/li>\n<\/ul>\n<p>o In a sail boat, the systems are integrated\u2014balance, steering, and other properties of the sail<\/p>\n<p>o Other, seemingly more complex systems, such as a rocket, are actually simpler.<\/p>\n<ul>\n<li>Two vs. four stroke. Two-stroke\u2014as you draw in fresh mixture, you exhaust from the previous combustion; the two-stroke exhaust may let out unburned fuel. If you solve the environmental problem, you would have a lighter engine because you do not need a valve. In a four-stroke engine, one stroke pulls in and compresses fuel then ignites it (power stroke), then the next stroke pushes out the exhaust.<\/li>\n<\/ul>\n<p>o The Tiger Cub has two valves to have a desirable mass flow rate. The cam controls how quickly the valves open and close<\/p>\n<ul>\n<li>Engine cooling\u2014require heat exchange between the engine and the outside air<\/li>\n<li>Overview of aerodynamic forces on ground vehicles<\/li>\n<\/ul>\n<p>CARBURATION<\/p>\n<ul>\n<li>Venturi effect: for an incompressible flow, a reduction of area causes an increase in local flow velocity and a consequent decrease in pressure.<\/li>\n<\/ul>\n<p>o Always have high velocity, low pressure<\/p>\n<ul>\n<li>The carburetor then fulfills 3 primary functions:<\/li>\n<\/ul>\n<p>o Control engine power by adjusting the air intake flow<\/p>\n<p>o Meter the fuel flow in the air flow aspirated maintaining the ratio air\/fuel to optimal values throughout the engine operating range<\/p>\n<p>o Homogenize the mixture of air and fuel to enable the subsequent combustion<\/p>\n<ul>\n<li>It is possible to obtain optimal thickness, spacing of the fins by mathematical computations<\/li>\n<li>There are two approaches to improving design: evolutionary and computational<\/li>\n<\/ul>\n<p>External aerodynamics<\/p>\n<ul>\n<li>Even with seemingly benign topics, it is hard to optimize,<\/li>\n<li>Hybrid between electric bike and moped is most efficient<\/li>\n<li>The speed at which the oil moves around is quite low; our motorcycle has a dry sump reduces the complexity of the system; if we had a<\/li>\n<li>Land speed records<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Notes by Eric: Professor Littman was not here today. In his absence, we were joined by a guest: Professor Luigi Martinelli Broad overview of the role of fluid mechanics, and more generally whatever happens when you try to move against air or water Whenever you are doing mundane tasks, you are dealing with fluid flows. &hellip; <a href=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/2018\/08\/09\/notes-by-eric\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;27 February 2018&#8221;<\/span><\/a><\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-33","post","type-post","status-publish","format-standard","hentry","category-diary"],"_links":{"self":[{"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/posts\/33","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/comments?post=33"}],"version-history":[{"count":2,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/posts\/33\/revisions"}],"predecessor-version":[{"id":60,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/posts\/33\/revisions\/60"}],"wp:attachment":[{"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/media?parent=33"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/categories?post=33"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/tags?post=33"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}