{"id":160138,"date":"2022-09-26T10:00:37","date_gmt":"2022-09-26T10:00:37","guid":{"rendered":"\/knowledge\/forums\/topic\/discovery-aim-tutorial-backwards-facing-step\/"},"modified":"2023-08-16T06:33:35","modified_gmt":"2023-08-16T06:33:35","slug":"discovery-aim-tutorial-backwards-facing-step","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/discovery-aim-tutorial-backwards-facing-step\/","title":{"rendered":"Discovery AIM tutorial &#8211; Backwards Facing Step"},"content":{"rendered":"<p><strong>This\u00a0example is taken from\u00a0<u><a href=\"https:\/\/confluence.cornell.edu\/display\/SIMULATION\/ANSYS+AIM+-+Backwards+Facing+Step\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">Cornell University&#8217;s ANSYS AIM Learning Modules<\/a><\/u><\/strong><\/p>\n<hr \/>\n<nav class=\"toc\">Contents<\/p>\n<ol class=\"toc__section -lev0\">\n<li class=\"toc__item -lev0\">Problem Specification<\/li>\n<li class=\"toc__item -lev0\">Pre-Analysis<\/li>\n<li class=\"toc__item -lev0\">Geometry\u00a0&amp; Mesh<\/li>\n<li class=\"toc__item -lev0\">Physics Setup<\/li>\n<li class=\"toc__item -lev0\">Results Evaluation<\/li>\n<li class=\"toc__item -lev0\">Validation<\/li>\n<\/ol>\n<\/nav>\n<h4 content_id=\"problem-specification\" class=\"toc__permalink\" content_id=\"problem-specification\" class=\"toc__permalink\"  id=\"PROBLEM-SPECIFICATION\">Problem Specification<\/h4>\n<p>Separation and reattachment of turbulent flow occurs as the fluid encounters a backwards facing step and eventually reaches the floor. Consider the diagram below which illustrates the problem.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-157120\" src=\"\/knowledge\/wp-content\/uploads\/sites\/4\/2022\/08\/hg98-1.png\" alt=\" width=\"512\" height=\"174\" \/><\/p>\n<p>A developed, turbulent, steady flow enters through an inlet, passes over a backwards facing step and then reaches the ground. In this demonstration, an enclosure will need to be created around the step and air will be used as the flow material. Air will enter via an inlet at the top step at a speed of 0.4 m\/s, with a density of 1.23 kg\/m^2 and dynamic viscosity of 1.86e-5 Ns\/m^2. From this data, the Reynold\u2019s number can be calculated to be about 5000.<\/p>\n<hr \/>\n<h4 content_id=\"pre-analysis\" class=\"toc__permalink\" content_id=\"pre-analysis\" class=\"toc__permalink\"  id=\"PRE-ANALYSIS\"><strong>Pre-Analysis<\/strong><\/h4>\n<p>The incompressible Navier-Stokes momentum and mass continuity equations are used as the governing equations for this flow. The modified Navier-Stokes and mass continuity equations are as follows, respectively.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-157122\" src=\"\/knowledge\/wp-content\/uploads\/sites\/4\/2022\/08\/hg99-1.png\" alt=\" width=\"410\" height=\"109\" \/><\/p>\n<hr \/>\n<h4 content_id=\"geometryamp-mesh\" class=\"toc__permalink\" content_id=\"geometryamp-mesh\" class=\"toc__permalink\"  id=\"GEOMETRY-MESH\">Geometry\u00a0&amp; Mesh<\/h4>\n<p><a style=\"color:#1E6DDC;font-weight:bold;text-decoration:none;\"  href=\"https:\/\/ansys13.ansys.com\/KnowledgeArticles\/Discovery\/StepsSV.zip\" download>Download the file here<\/a><\/p>\n<p>In this video, you will learn how to import the geometry in Discovery AIM and how to generate mesh in the computational fluid domain.<\/p>\n<p><iframe loading=\"lazy\" class=\"vidyard_iframe\" src=\"https:\/\/play.vidyard.com\/rdVJtovg3u9AsodMKDmtXA.html?\" width=\"700\" height=\"360\" frameborder=\"0\" scrolling=\"no\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<hr \/>\n<h4 content_id=\"physics-setup\" class=\"toc__permalink\" content_id=\"physics-setup\" class=\"toc__permalink\"  id=\"PHYSICS-SETUP\">Physics Setup<\/h4>\n<p>In this video, you will learn how to edit material properties and specify fluid flow conditions.<\/p>\n<p><iframe loading=\"lazy\" class=\"vidyard_iframe\" src=\"https:\/\/play.vidyard.com\/CpAjjdHVC93nrG2pqH31fM.html?\" width=\"700\" height=\"360\" frameborder=\"0\" scrolling=\"no\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<hr \/>\n<h4 content_id=\"results-evaluation\" class=\"toc__permalink\" content_id=\"results-evaluation\" class=\"toc__permalink\"  id=\"RESULTS-EVALUATION\">Results Evaluation<\/h4>\n<p>In this video, you will learn how to evaluate velocity vectors and velocity contour in the flow domain.<\/p>\n<p><iframe loading=\"lazy\" class=\"vidyard_iframe\" src=\"https:\/\/play.vidyard.com\/Ye4LhRnK4gHvSsyn7QQwDY.html?\" width=\"700\" height=\"360\" frameborder=\"0\" scrolling=\"no\" allowfullscreen=\"allowfullscreen\"><span data-mce-type=\"bookmark\" style=\"display: inline-block; width: 0px; overflow: hidden; line-height: 0;\" class=\"mce_SELRES_start\">\ufeff<\/span><\/iframe><\/p>\n<hr \/>\n<h4 content_id=\"validation\" class=\"toc__permalink\" content_id=\"validation\" class=\"toc__permalink\"  id=\"VALIDATION\">Validation<\/h4>\n<p>Since so many study cases have been done for this problem, it is easiest to validate our simulation against those cases. In this tutorial, \u201cBackward-Facing Step Flows for Various Expansion Ratios at Low and Moderate Reynolds Numbers\u201d by G. Biswas, M. Breuer, and F. Durst will be our study case.\u00a0A streamline plot from the study case is shown below. It can be seen that the simulated flow behaved just as we had expected it to in our problem specification and the case study.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-160138","topic","type-topic","status-publish","hentry","topic-tag-aim-tutorial","topic-tag-discovery-aim","topic-tag-fluids"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_wp_page_template":["default"],"_bbp_last_active_time":["09-13-2022  20:20:15"],"_bbp_forum_id":["159552"],"_btv_view_count":["1946"],"family":[""],"application_name":[""],"product_version":[""]},"test":"watchlearnansys-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics\/160138","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics\/160138\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/media?parent=160138"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}