{"id":1968,"date":"2020-11-13T12:05:19","date_gmt":"2020-11-13T17:05:19","guid":{"rendered":"https:\/\/engineering.jhu.edu\/zaki\/?page_id=1968"},"modified":"2021-09-18T20:23:40","modified_gmt":"2021-09-19T00:23:40","slug":"data-assimilation","status":"publish","type":"page","link":"https:\/\/engineering.jhu.edu\/zaki\/research\/data-assimilation\/","title":{"rendered":"Data assimilation"},"content":{"rendered":"<div id=\"kgvid_kgvid_0_wrapper\" class=\"kgvid_wrapper kgvid_wrapper_inline kgvid_wrapper_inline_left\">\n\t\t\t<div id=\"video_kgvid_0_div\" class=\"fitvidsignore kgvid_videodiv\" data-id=\"kgvid_0\" data-kgvid_video_vars=\"{&quot;id&quot;:&quot;kgvid_0&quot;,&quot;attachment_id&quot;:2042,&quot;player_type&quot;:&quot;Video.js v8&quot;,&quot;width&quot;:&quot;640&quot;,&quot;height&quot;:&quot;360&quot;,&quot;fullwidth&quot;:&quot;false&quot;,&quot;fixed_aspect&quot;:&quot;false&quot;,&quot;countable&quot;:true,&quot;count_views&quot;:&quot;quarters&quot;,&quot;start&quot;:&quot;&quot;,&quot;autoplay&quot;:&quot;false&quot;,&quot;pauseothervideos&quot;:&quot;false&quot;,&quot;set_volume&quot;:&quot;1&quot;,&quot;muted&quot;:&quot;false&quot;,&quot;meta&quot;:false,&quot;endofvideooverlay&quot;:&quot;&quot;,&quot;resize&quot;:&quot;true&quot;,&quot;auto_res&quot;:&quot;automatic&quot;,&quot;pixel_ratio&quot;:&quot;true&quot;,&quot;right_click&quot;:&quot;on&quot;,&quot;playback_rate&quot;:&quot;false&quot;,&quot;title&quot;:&quot;Zaki_video_trimmed&quot;,&quot;skip_buttons&quot;:[],&quot;nativecontrolsfortouch&quot;:&quot;true&quot;,&quot;locale&quot;:&quot;en&quot;,&quot;enable_resolutions_plugin&quot;:&quot;true&quot;,&quot;default_res&quot;:false}\" itemprop=\"video\" itemscope itemtype=\"https:\/\/schema.org\/VideoObject\"><meta itemprop=\"thumbnailUrl\" content=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/12\/Thumbnail.png\"><meta itemprop=\"embedUrl\" content=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/12\/Zaki_video_trimmed.mp4\"><meta itemprop=\"contentUrl\" content=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/12\/Zaki_video_trimmed.mp4\"><meta itemprop=\"name\" content=\"Zaki_video_trimmed\"><meta itemprop=\"description\" content=\"Video\"><meta itemprop=\"uploadDate\" content=\"2020-12-06T09:21:55-05:00\">\n\t\t\t\t<video id=\"video_kgvid_0\" playsinline controls preload=\"metadata\" poster=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/12\/Thumbnail.png\" width=\"640\" height=\"360\" class=\"fitvidsignore video-js kg-video-js-skin\">\n\t\t\t\t\t<source src=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/12\/Zaki_video_trimmed.mp4?id=0\" type=\"video\/mp4\" data-res=\"1080p\">\n\t\t\t\t\t<source src=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/12\/Zaki_video_trimmed-360.mp4?id=0\" type=\"video\/mp4\" data-res=\"360p\">\n\t\t\t\t<\/video>\n\t\t\t<\/div>\n\t\t<\/div>\n<p>&nbsp;<\/p>\n<p><span style=\"font-size: 1rem;\">The intriguing fluid-dynamical phenomena that take place during transition to turbulence and <\/span><span style=\"font-size: 1rem;\">\u00a0in fully turbulent flows are commonly probed by\u00a0experiments and simulations. Experiments contend with a trade-off between field of view and spatio-temporal resolution as well as the difficulty of directly probing quantities of interest. On the other hand, simulations can explicitly compute any term in the flow equations; but simulations invoke idealizations and modeling assumptions in extreme flow\u00a0<\/span>regimes (e.g. high Mach and\u00a0<span style=\"font-size: 1rem;\">Reynolds numbers). And no matter the approach, once we step beyond canonical configurations, the scarcity of available observations frustrates both experimental and computational researchers alike.<\/span><\/p>\n<p><span style=\"font-size: 1rem;\">In order to leverage\u00a0<\/span>the<span style=\"font-size: 1rem;\">\u00a0strengths of\u00a0<\/span>simulations<span style=\"font-size: 1rem;\">\u00a0and experiments and also mitigate their respective deficiencies,\u00a0<\/span><span style=\"font-size: 1rem;\">our group developed the framework of observation-infused simulations. We directly infuse the available and incomplete observations data in the simulations, and we predict the optimal interpretation of the missing content.<\/span><\/p>\n<p><span style=\"font-size: 1rem;\"><a href=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/11\/graph_abstract.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-1957\" src=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/11\/graph_abstract-300x250.jpg\" alt=\"\" width=\"450\" height=\"374\" srcset=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/11\/graph_abstract-300x250.jpg 300w, https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/11\/graph_abstract-624x519.jpg 624w, https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/11\/graph_abstract.jpg 709w\" sizes=\"auto, (max-width: 450px) 100vw, 450px\" \/><\/a><\/span><\/p>\n<p align=\"left\">The figure above shows an example of under-resolved observations in turbulent channel flow and the outcome of infusing these measurements in our simulation.<\/p>\n<ul>\n<li>Top panel: \u00a0The line contours represent the true (unknown) velocity field that is probed, and the colored pixels are the available under-resolved measurements. \u00a0Our objective is to reconstruct the full flow from just the observations.<\/li>\n<li>Bottom panel: \u00a0The color contours show our prediction of the instantaneous velocity field, and they are compared to the lines which are the (unknown) truth.<\/li>\n<\/ul>\n<p align=\"left\">Our group has developed adjoint- (4DVar) and ensemble- (EnVar) variational techniques to solve these problems as well as machine learning (ML) techniques. \u00a0We have also developed new techniques to (1) determine the minimum sensor resolution to reconstruct turbulence, \u00a0(2) optimize the placement of sensors to maximize the accuracy of the flow prediction. \u00a0Ongoing projects including the following:<\/p>\n<ul>\n<li>Prediction of upstream disturbances in transitional hypersonic flows from limited observations;<\/li>\n<li>Reconstruction of remote scalar sources and velocity field in stratified turbulence from scarce measurements;<\/li>\n<li>Prediction of high-Reynolds-number separated flows from limited observations.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>&nbsp; The intriguing fluid-dynamical phenomena that take place during transition to turbulence and \u00a0in fully turbulent flows are commonly probed by\u00a0experiments and simulations. Experiments contend with a trade-off between field of view and spatio-temporal resolution as well as the difficulty of directly probing quantities of interest. On the other hand, simulations can explicitly compute any [&hellip;]<\/p>\n","protected":false},"author":127,"featured_media":0,"parent":30,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"class_list":["post-1968","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Data assimilation - Flow Science and Engineering<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/engineering.jhu.edu\/zaki\/research\/data-assimilation\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Data assimilation - Flow Science and Engineering\" \/>\n<meta property=\"og:description\" content=\"&nbsp; The intriguing fluid-dynamical phenomena that take place during transition to turbulence and \u00a0in fully turbulent flows are commonly probed by\u00a0experiments and simulations. Experiments contend with a trade-off between field of view and spatio-temporal resolution as well as the difficulty of directly probing quantities of interest. On the other hand, simulations can explicitly compute any [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/engineering.jhu.edu\/zaki\/research\/data-assimilation\/\" \/>\n<meta property=\"og:site_name\" content=\"Flow Science and Engineering\" \/>\n<meta property=\"article:modified_time\" content=\"2021-09-19T00:23:40+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/engineering.jhu.edu\/zaki\/wp-content\/uploads\/2020\/11\/graph_abstract-300x250.jpg\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/data-assimilation\\\/\",\"url\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/data-assimilation\\\/\",\"name\":\"Data assimilation - Flow Science and Engineering\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/data-assimilation\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/data-assimilation\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/wp-content\\\/uploads\\\/2020\\\/11\\\/graph_abstract-300x250.jpg\",\"datePublished\":\"2020-11-13T17:05:19+00:00\",\"dateModified\":\"2021-09-19T00:23:40+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/data-assimilation\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/data-assimilation\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/data-assimilation\\\/#primaryimage\",\"url\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/wp-content\\\/uploads\\\/2020\\\/11\\\/graph_abstract.jpg\",\"contentUrl\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/wp-content\\\/uploads\\\/2020\\\/11\\\/graph_abstract.jpg\",\"width\":709,\"height\":590},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/data-assimilation\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Research\",\"item\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/research\\\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Data assimilation\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/#website\",\"url\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/\",\"name\":\"Flow Science and Engineering\",\"description\":\"Tamer Zaki&#039;s Research Group\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/engineering.jhu.edu\\\/zaki\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Data assimilation - Flow Science and Engineering","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/engineering.jhu.edu\/zaki\/research\/data-assimilation\/","og_locale":"en_US","og_type":"article","og_title":"Data assimilation - Flow Science and Engineering","og_description":"&nbsp; The intriguing fluid-dynamical phenomena that take place during transition to turbulence and \u00a0in fully turbulent flows are commonly probed by\u00a0experiments and simulations. 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