{"id":11158,"date":"2017-04-11T14:47:08","date_gmt":"2017-04-11T17:47:08","guid":{"rendered":"http:\/\/www.rcgi.poli.usp.br\/?page_id=11158\/"},"modified":"2017-04-11T14:47:08","modified_gmt":"2017-04-11T17:47:08","slug":"129-bifurcations-buckling-and-flow-transitions","status":"publish","type":"page","link":"https:\/\/sites.usp.br\/rcgi\/129-bifurcations-buckling-and-flow-transitions\/","title":{"rendered":"129 &#8211; Bifurcations, buckling and flow transitions"},"content":{"rendered":"<p>[vc_row][vc_column width=&#8221;2\/3&#8243;][vc_column_text]<\/p>\n<h3 style=\"text-align: justify\"><strong>19\u00a0APRIL 2017 | SEMINAR\u00a0<\/strong><\/h3>\n<h4><strong>BIFURCATIONS, BUCKLING AND FLOW TRANSITIONS<\/strong><br \/>\n<em>Scalable bifurcation analysis of nonlinear partial differential equations and variational inequalities<\/em><\/h4>\n<p>[divider style=&#8221;solid&#8221; padding_top=&#8221;15&#8243; padding_bottom=&#8221;0&#8243;][\/divider]<\/p>\n<h4><strong>Prof Patrick Farrell<br \/>\nMathematical Institute, University of Oxford, England<\/strong><\/h4>\n<p>[divider style=&#8221;solid&#8221; padding_top=&#8221;0&#8243; padding_bottom=&#8221;15&#8243;][\/divider]<\/p>\n<h4><strong>Abstract<\/strong><\/h4>\n<p>Computing the solutions $u$ of an equation $f(u, \\lambda) = 0$ as the parameter $\\lambda$ is varied is a central task in applied mathematics and engineering. In this talk I will present a new algorithm, deflated continuation, for this task.<\/p>\n<p>Deflated continuation has three main advantages. First, it is capable of computing disconnected bifurcation diagrams; previous algorithms only aimed to compute that part of the bifurcation diagram continuously connected to the initial data. Second, its implementation is extremely simple: it only requires a minor modification to any existing Newton-based solver. Third, it can scale to very large discretisations if a good preconditioner is available.<\/p>\n<p>Among other problems, we will apply this to a famous singularly perturbed ODE, Carrier&#8217;s problem. The computations reveal a striking and beautiful bifurcation diagram, with an infinite sequence of alternating pitchfork and fold bifurcations as the singular perturbation parameter tends to zero. The analysis yields a novel and complete taxonomy of the solutions to the problem, and demonstrates that a claim of Bender &amp; Orszag (1999) is incorrect. We will also use the algorithm to calculate distinct local minimisers of a topology optimisation problem via the combination of deflated continuation and a semismooth Newton method.[\/vc_column_text][vc_empty_space height=&#8221;35px&#8221;][vc_toggle title=&#8221;Personal bio of Prof Patrick Farrell&#8221; style=&#8221;square&#8221; el_id=&#8221;1472579256290-0895b46c-c616&#8243;]<\/p>\n<p style=\"text-align: justify\"><strong>Employment:<\/strong> Associate Professor in Numerical Analysis and Scientific Computing Mathematical Institute , University of Oxford and Tutorial Fellow in Applied Mathematics &#8211; Oriel College, University of Oxford<\/p>\n<p style=\"text-align: justify\"><strong>Qualifications:<\/strong> PhD in Computational Physics &#8211; Imperial College London &#8211; <strong>Thesis title:<\/strong> Galerkin projection of discrete fields via supermesh construction<\/p>\n<p style=\"text-align: justify\"><strong>Prizes:<\/strong> Association of Computational Mechanics in Engineering 2010; Finalist and UK Representative, European Community on Computational Methods in Applied Sciences Award; Fox Prize, 2015, Wilkinson Prize 2015<\/p>\n<p>[\/vc_toggle][vc_empty_space height=&#8221;10px&#8221;][\/vc_column][vc_column width=&#8221;1\/3&#8243; css=&#8221;.vc_custom_1458822913427{margin-left: 15px !important;padding-top: 15px !important;padding-right: 15px !important;padding-bottom: 15px !important;padding-left: 15px !important;background-color: #f1f1f2 !important;}&#8221;][vc_custom_heading text=&#8221;Details&#8221; font_container=&#8221;tag:h2|font_size:20|text_align:left&#8221; google_fonts=&#8221;font_family:Raleway%3A100%2C200%2C300%2Cregular%2C500%2C600%2C700%2C800%2C900|font_style:700%20bold%20regular%3A700%3Anormal&#8221;][vc_column_text]<strong>Date:<\/strong>\u00a019\u00a0APRIL 2017<br \/>\n<strong>Time:<\/strong> 2:00 pm<\/p>\n<p><strong>Address<\/strong><br \/>\nRCGI &#8211; Research Centre for Gas Innovation<br \/>\nPr\u00e9dio da Engenharia Mec\u00e2nica e Naval<br \/>\nAv. Professor Mello Moraes, 2231<br \/>\nUniversity of S\u00e3o Paulo<br \/>\nEscola Polit\u00e9cnica | Cidade Universit\u00e1ria<br \/>\nS\u00e3o Paulo &#8211; SP, 05508-030 | Brazil<\/p>\n<p><strong>Phone: <\/strong>+55 11 2648-6226[\/vc_column_text][vc_separator color=&#8221;#424242&#8243; padding_top=&#8221;12&#8243; padding_bottom=&#8221;12&#8243;][vc_raw_html]JTNDZGl2JTIwY2xhc3MlM0QlMjJmYi1zaGFyZS1idXR0b24lMjIlMjBkYXRhLWhyZWYlM0QlMjJodHRwJTNBJTJGJTJGd3d3LnJjZ2kucG9saS51c3AuYnIlMkZldmVudHMtMjAxNiUyRjEyOS1iaWZ1cmNhdGlvbnMtYnVja2xpbmctYW5kLWZsb3ctdHJhbnNpdGlvbnMlMkYlMjIlMjBkYXRhLWxheW91dCUzRCUyMmJ1dHRvbiUyMiUzRSUzQyUyRmRpdiUzRQ==[\/vc_raw_html][vc_empty_space height=&#8221;20px&#8221;][vc_tweetmeme][vc_separator color=&#8221;#424242&#8243; padding_top=&#8221;12&#8243; padding_bottom=&#8221;12&#8243;][vc_button title=&#8221;Download the event poster&#8221; target=&#8221;_blank&#8221; icon_fontawesome=&#8221;fa fa-angle-down&#8221; align=&#8221;left&#8221; add_icon=&#8221;true&#8221; href=&#8221;\/wp-content\/uploads\/2017\/04\/poster_19.04.2017.pdf&#8221;][\/vc_column][\/vc_row]<\/p>\n","protected":false},"excerpt":{"rendered":"<p>[vc_row][vc_column width=&#8221;2\/3&#8243;][vc_column_text] 19\u00a0APRIL 2017 | SEMINAR\u00a0 BIFURCATIONS, BUCKLING AND FLOW TRANSITIONS Scalable bifurcation analysis of nonlinear partial differential equations and variational inequalities [divider style=&#8221;solid&#8221; padding_top=&#8221;15&#8243; padding_bottom=&#8221;0&#8243;][\/divider] Prof Patrick Farrell Mathematical &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/sites.usp.br\/rcgi\/129-bifurcations-buckling-and-flow-transitions\/\" class=\"more-link\">Continue lendo<span class=\"screen-reader-text\"> &#8220;129 &#8211; Bifurcations, buckling and flow transitions&#8221;<\/span><\/a><\/p>\n","protected":false},"author":23409,"featured_media":0,"parent":0,"menu_order":129,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_EventAllDay":false,"_EventTimezone":"","_EventStartDate":"","_EventEndDate":"","_EventStartDateUTC":"","_EventEndDateUTC":"","_EventShowMap":false,"_EventShowMapLink":false,"_EventURL":"","_EventCost":"","_EventCostDescription":"","_EventCurrencySymbol":"","_EventCurrencyCode":"","_EventCurrencyPosition":"","_EventDateTimeSeparator":"","_EventTimeRangeSeparator":"","_EventOrganizerID":[],"_EventVenueID":[],"_OrganizerEmail":"","_OrganizerPhone":"","_OrganizerWebsite":"","_VenueAddress":"","_VenueCity":"","_VenueCountry":"","_VenueProvince":"","_VenueState":"","_VenueZip":"","_VenuePhone":"","_VenueURL":"","_VenueStateProvince":"","_VenueLat":"","_VenueLng":"","_VenueShowMap":false,"_VenueShowMapLink":false,"footnotes":"","_links_to":"","_links_to_target":""},"class_list":["post-11158","page","type-page","status-publish","hentry"],"acf":[],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/sites.usp.br\/rcgi\/wp-json\/wp\/v2\/pages\/11158","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.usp.br\/rcgi\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sites.usp.br\/rcgi\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sites.usp.br\/rcgi\/wp-json\/wp\/v2\/users\/23409"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.usp.br\/rcgi\/wp-json\/wp\/v2\/comments?post=11158"}],"version-history":[{"count":0,"href":"https:\/\/sites.usp.br\/rcgi\/wp-json\/wp\/v2\/pages\/11158\/revisions"}],"wp:attachment":[{"href":"https:\/\/sites.usp.br\/rcgi\/wp-json\/wp\/v2\/media?parent=11158"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}