{"id":2900,"date":"2020-07-10T18:38:43","date_gmt":"2020-07-10T16:38:43","guid":{"rendered":"https:\/\/c2019.lemma-ing.com\/?page_id=2900"},"modified":"2020-08-31T10:43:12","modified_gmt":"2020-08-31T08:43:12","slug":"dedicated-solver-numerical-basin","status":"publish","type":"page","link":"https:\/\/www.lemma-ing.com\/?page_id=2900","title":{"rendered":"DEDICATED SOLVER : numerical basin"},"content":{"rendered":"<p><a title=\"NICEFLOW\u00ae : The ultimate strongly coupled CFSD solver\" href=\"\/?page_id=2923\"><strong>NICEFLOW\u00ae<\/strong><\/a>&nbsp; is used in a wide range of industries across all industry sectors. &nbsp;Once again, LEMMA team has been challenged in many benchmarks to prove that there is no need to have a 30 years old compagny to get the best results in marine or off-shore specific sector. <a title=\"NICEFLOW\u00ae : The ultimate strongly coupled CFSD solver\" href=\"\/?page_id=2923\"><strong>NICEFLOW\u00ae<\/strong><\/a>&nbsp;is now well established as the most full-spectrum and accurate CFD solution, with strong reference&nbsp;on this market.<\/p>\n<h2>The numerical basin technology<\/h2>\n<p style=\"text-align: justify;\">In a high competitive industrial context, the experimental tests, even at reduced scale, are costly and time consuming for a project : breadboards realisation, tests equipment availability, tests duration and results analysis. Willing to provide efficient innovating solutions within a cost reduction approach, LEMMA has developped the numerical basin concept with its combined expertises in numerical simulation and hydrodynamics.<br \/>\nLEMMA has developed new numerical methods, faster and more accurate, implemented with parallel algorithms in the CFD software <a title=\"NICEFLOW\u00ae : The ultimate strongly coupled CFSD solver\" href=\"\/?page_id=2923\"><strong>NICEFLOW\u00ae<\/strong><\/a>, which simulates the real turbulent flow of vessels behavior or oil platforms (floating structures).<br \/>\nThe numerical performances of the numerical basin enable to seize the reality of physical phenomenon at scale 1. We now are able to<\/p>\n<ul>\n<li style=\"text-align: justify;\">generate <strong>any type of wave<\/strong>&nbsp;: monochromatic, bi-chromatic, regular wave, regular wave packet, irregular waves , within any number of oscillating flaps or spectral methods. Linear or non linear approach considered to generate waves is coupled to RANS or LES-VMS models and allows us to perform very accurate simulations, up to order 6 in space (see example below untitled <a title=\"Featured technology: high order numerical methods\" href=\"\/?page_id=1285\">Numerical investigation of thermally stratified wake<\/a>).<\/li>\n<li style=\"text-align: justify;\">take into account <strong>current and wind<\/strong> without velocity limitation<\/li>\n<li style=\"text-align: justify;\">modelise <strong>anchors<\/strong> (linear and non linear) linked to floatting bodies<\/li>\n<li style=\"text-align: justify;\">study <strong>sea-keeping&nbsp;<\/strong>and manoeuvrability or non linear roll damping.<\/li>\n<\/ul>\n<div>\n<div class=\"su-row\">\n<div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-numerical.png\" width=\"460\"><\/p>\n<p><center><strong>Numerical basin : wave and\/or current generation.<\/strong><\/center><\/p>\n<\/div><\/div>\n<div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-analytical.png\" width=\"300\"><\/p>\n<p><center><strong>Numerical basin : analytical data.<\/strong><\/center><\/p>\n<\/div><\/div>\n<\/div>\n<\/div>\n<h2>Main benefits of our technology<\/h2>\n<p style=\"text-align: justify;\">Our initial aim was to develop a new technology to get both more accurate results within a time frame divided by 3 to 15 (depending on the application) vs other classical approaches implemented in most of famous other softwares packages. Clearly <strong>we want to change the standards in marine and offshore CFD market<\/strong>. How to achieve it ? By combining our background in applied mathematics and our knowledge in hydrodynamics. The method that we use allows us to impose spectral incident waves while reflected waves are calculated using a classical RANS model: that&#8217;s the basics of the SWENSE approach initially proposed by the ECN research group (see the picture below).<\/p>\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-swense.png\" width=\"600\"><\/p>\n<p><center><strong>SWENSE decomposition. From R. Luquet thesis, ECN.<\/strong><\/center><\/p>\n<h2>Academic validation test cases<\/h2>\n<div class=\"su-accordion su-u-trim\">\n<div class=\"su-spoiler su-spoiler-style-fancy su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>3D truncated cylinder in waves<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\">\n<p>The following simulation on the 3D cylinder takes only three hours on a laptop&nbsp; computer for 18 seconds of physical time (10 periods). The mesh has a complexity of 600 000 nodes. The drag force exerted on the cylinder by impacting incident waves &nbsp;is calculated along time and post processed using a FFT tool. The wave period is 1.8 s, height 0.237 m and steepness is about 4.6%.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-cylinder.png\" width=\"300\"><\/p>\n<p><center><strong>Free surface elevation around the cylinder..<\/strong><\/center><\/p>\n<p>The numerical results are compared with experimental ones (Krokstad &amp; Stanberg, 1995) : the first two harmonics of the drag force are shown on the table below, with a very satisfying agreement.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-data.png\" width=\"300\"><\/p>\n<p><center><strong>Validation data.<\/strong><\/center><\/p>\n<p class=\"thescrollup\"><a href=\"#top\"><img decoding=\"async\" src=\"https:\/\/www.lemma-ing.com\/wp-content\/plugins\/scrollup\/arrow.png\" alt=\"&#9660; Sommet\" title=\"&#9660; Sommet\" \/><\/a><\/p>\n<\/div><\/div>\n<div class=\"su-spoiler su-spoiler-style-fancy su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Edge impacting free surface<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\">\n<p style=\"text-align: justify;\">Initially,&nbsp;the wedge is falling under the gravity and, after the impact,&nbsp;its motion results from its interaction with the water. For this simulation, the geometric mesh adaptation strategy has been applied. A sequence of three quasi embedded meshes containing respectively 3 069, 10 432 and 37 146&nbsp;vertices has been generated. They correspond to a division by two of spatial step size. This sequence will enable us to study the convergence of the method. During the simulation, when the mesh becomes too distorted due to the displacement of the wedge, the adapted mesh is regenerated with the same geometric and size criteria. CPU time = 6 hours on 1 processor. For further details, see the publication [<a title=\"Bibliographical ressources\" href=\"\/?page_id=69\">Allain &amp; al., OMAE 2009<\/a>]\n<div class=\"su-row\">\n<div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\n<p style=\"text-align: center;\"><iframe loading=\"lazy\" src=\"https:\/\/www.youtube-nocookie.com\/embed\/YDhfF4C5ESc\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen=\"\" width=\"560\" height=\"315\" frameborder=\"0\"><\/iframe><\/p>\n<p><center><strong>2D edge impacting free surface, mesh view.<\/strong><\/center><\/p>\n<\/div><\/div>\n<div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\n<p style=\"text-align: center;\"><iframe loading=\"lazy\" src=\"https:\/\/www.youtube-nocookie.com\/embed\/49TkUbZu1No\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen=\"\" width=\"560\" height=\"315\" frameborder=\"0\"><\/iframe><\/p>\n<p><center><strong>2D edge impacting free surface calculated with improved level set formulation.<\/strong><\/center><br \/>\n<\/div><\/div>\n<\/div>\n<div class=\"su-row\">\n<div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-vertical.png\" width=\"500\"><\/p>\n<p><center><strong>2D falling edge. Plot of vertical acceleration.<\/strong><\/center><\/p>\n<\/div><\/div>\n<div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-angular.png\" width=\"500\"><\/p>\n<p><center><strong>2D falling edge. Plot of angular acceleration.<\/strong><\/center><\/p>\n<\/div><\/div>\n<\/div>\n<p class=\"thescrollup\"><a href=\"#top\"><img decoding=\"async\" src=\"https:\/\/www.lemma-ing.com\/wp-content\/plugins\/scrollup\/arrow.png\" alt=\"&#9660; Sommet\" title=\"&#9660; Sommet\" \/><\/a><\/p>\n<\/div><\/div>\n<div class=\"su-spoiler su-spoiler-style-fancy su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>VIV &nbsp;on multiple cylinders with hybrid RANS-VMS<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\">\n<p style=\"text-align: justify;\">As a beginning and before simulating VIV problems on multiple cylinders, <a title=\"NICEFLOW\u00ae : The ultimate strongly coupled CFSD solver\" href=\"\/?page_id=2923\"><strong>NICEFLOW\u00ae<\/strong><\/a> is validated on an academic case dealing with the flow around one cylinder at different Reynolds numbers, ranging from &nbsp;3900 to 20000. These simulations are performed with our hybrid RANS-VMS model and snapshots are showed on the following pictures. This work has been published in [<a title=\"Bibliographical resources\" href=\"\/?page_id=69\">Computers &amp; Fluids, 2011<\/a>]. Please <a title=\"Directions &amp; contact form\" href=\"\/?page_id=117\" target=\"_blank\" rel=\"noopener noreferrer\">ask us<\/a> if you are interested in this work.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-hybrid.png\" width=\"650\"><\/p>\n<p><center><strong>Cylinder at different Reynolds numbers. Hybrid RANS-VMS model.<\/strong><\/center><\/p>\n<p class=\"thescrollup\"><a href=\"#top\"><img decoding=\"async\" src=\"https:\/\/www.lemma-ing.com\/wp-content\/plugins\/scrollup\/arrow.png\" alt=\"&#9660; Sommet\" title=\"&#9660; Sommet\" \/><\/a><\/p>\n<\/div><\/div>\n<\/div>\n<h2>Marine applications industrial cases<\/h2>\n<div class=\"su-accordion su-u-trim\">\n<div class=\"su-spoiler su-spoiler-style-fancy su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Numerical investigation of thermally stratified wake<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\">\n<p>For further details about this study, please click <a title=\"Featured technology: high order numerical methods\" href=\"\/?page_id=1285\" target=\"_blank\" rel=\"noopener noreferrer\">here<\/a>.<br \/>\n<p class=\"thescrollup\"><a href=\"#top\"><img decoding=\"async\" src=\"https:\/\/www.lemma-ing.com\/wp-content\/plugins\/scrollup\/arrow.png\" alt=\"&#9660; Sommet\" title=\"&#9660; Sommet\" \/><\/a><\/p>\n<\/div><\/div>\n<div class=\"su-spoiler su-spoiler-style-fancy su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Resistance in calm water and added resistance in waves<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\">\n<p>For further details about this study, performed with <a href=\"https:\/\/ulstein.com\/\">ULSTEIN <\/a>, please <a href=\"wp-content\/uploads\/Published-Paper-25-11-2016.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">click here<\/a> to download our last scientific paper published on this subject.<br \/>\n<p class=\"thescrollup\"><a href=\"#top\"><img decoding=\"async\" src=\"https:\/\/www.lemma-ing.com\/wp-content\/plugins\/scrollup\/arrow.png\" alt=\"&#9660; Sommet\" title=\"&#9660; Sommet\" \/><\/a><\/p>\n<\/div><\/div>\n<div class=\"su-spoiler su-spoiler-style-fancy su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Sails performance study<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\">\n<p>This study shows the potential of intelligent mesh technology to capture the flow around sails. A first Euler calculation around the geometry is done very quickly (5 mn on a laptop)&nbsp; with a coarse mesh of 130 000 nodes. Then we use the intelligent mesh technology&nbsp; to get more accurate results at the design stage, within a calculation of 5 mn on 32 cores. Finally, for the final design stage, RANS calculation is realized by automatically inserting boundary layers around the sails.<\/p>\n<div class=\"su-row\">\n<div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-CAD.png\" width=\"350\"><\/p>\n<p><center><strong>Initial CAD geometry.<\/strong><\/center><\/p>\n<\/div><\/div>\n<div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-RANS.png\" width=\"350\"><\/p>\n<p><center><strong>Pressure field on sails &#8211; RANS calculation on coarse mesh.<\/strong><\/center><\/p>\n<\/div><\/div>\n<\/div>\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-adapt1.png\" width=\"700\"><\/p>\n<p><center><strong>Adapted mesh around sails.<\/strong><\/center><\/p>\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"\/wp-content\/uploads\/Dedicated-basin-adapt2.png\" width=\"500\"><\/p>\n<p><center><strong>Adapted mesh in the wake.<\/strong><\/center><br \/>\n<p class=\"thescrollup\"><a href=\"#top\"><img decoding=\"async\" src=\"https:\/\/www.lemma-ing.com\/wp-content\/plugins\/scrollup\/arrow.png\" alt=\"&#9660; Sommet\" title=\"&#9660; Sommet\" \/><\/a><\/p>\n<\/div><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>NICEFLOW\u00ae&nbsp; is used in a wide range of industries across all industry sectors. &nbsp;Once again, LEMMA team has been challenged in many benchmarks to prove that there is no need to have a 30 years old compagny to get the best results in marine or off-shore specific sector. NICEFLOW\u00ae&nbsp;is now well established as the most&#8230; <\/p>\n","protected":false},"author":229,"featured_media":0,"parent":2893,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"full-width.php","meta":{"footnotes":""},"class_list":["post-2900","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=\/wp\/v2\/pages\/2900","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=\/wp\/v2\/users\/229"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2900"}],"version-history":[{"count":6,"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=\/wp\/v2\/pages\/2900\/revisions"}],"predecessor-version":[{"id":3021,"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=\/wp\/v2\/pages\/2900\/revisions\/3021"}],"up":[{"embeddable":true,"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=\/wp\/v2\/pages\/2893"}],"wp:attachment":[{"href":"https:\/\/www.lemma-ing.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2900"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}