{"id":248,"date":"2026-07-01T10:00:00","date_gmt":"2026-07-01T10:00:00","guid":{"rendered":"https:\/\/www.auriga.polimi.it\/?p=248"},"modified":"2026-09-01T13:46:38","modified_gmt":"2026-09-01T13:46:38","slug":"aissaoui-research-stay-hzdr","status":"publish","type":"post","link":"https:\/\/www.auriga.polimi.it\/index.php\/aissaoui-research-stay-hzdr\/","title":{"rendered":"Djamel Eddine Aissaoui&#8217;s research stay at HZDR"},"content":{"rendered":"\n<p class=\"is-style-lede wp-block-paragraph\">Within AURIGA&#8217;s bubble-scale work package, Djamel Eddine Aissaoui is characterising the lift force on single bubbles in linear shear flow, using Particle Shadow Velocimetry at HZDR.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Single-bubble dynamics are targeted as a key building block for the project&#8217;s broader theoretical aim of modelling flow regime transitions in multi-phase fluid dynamics. Accurate closure models for the lift force are central to this effort, since the lateral migration of bubbles governs the local and global void-fraction distribution. While the lift coefficient is well characterised for bubbles rising in pure water, the ionic liquids screened in AURIGA&#8217;s experimental phase alter interfacial mobility and, in turn, the sign and magnitude of the lift force. This motivates a dedicated single-bubble lift-force study, following the approach developed by Hessenkemper et al., across a range of aqueous ionic-liquid mixtures, to support the reformulation of the drift-flux model.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/www.auriga.polimi.it\/wp-content\/uploads\/2026\/07\/djamel-hzdr.jpeg\" alt=\"Djamel Eddine Aissaoui with the multiphase-flow group during the research stay at HZDR\" class=\"wp-image-215\" srcset=\"https:\/\/www.auriga.polimi.it\/wp-content\/uploads\/2026\/07\/djamel-hzdr.jpeg 1024w, https:\/\/www.auriga.polimi.it\/wp-content\/uploads\/2026\/07\/djamel-hzdr-300x225.jpeg 300w, https:\/\/www.auriga.polimi.it\/wp-content\/uploads\/2026\/07\/djamel-hzdr-768x576.jpeg 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Djamel Eddine Aissaoui with the multiphase-flow group during the research stay at HZDR.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">The measurement<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Single bubbles are released into a vortex-driven bubble column designed to produce a well-defined linear shear flow in the surrounding liquid. Bubble and liquid-phase velocities are measured simultaneously using Particle Shadow Velocimetry (PSV), a direct in-line illumination technique. Bubble trajectories are extracted through automated detection and tracking, and the local lift coefficient is obtained by solving a lateral force balance along each bubble&#8217;s path, following Ziegenhein et al. (2018) and Hessenkemper et al. (2020), accounting for the drag, virtual mass and buoyancy forces acting on the bubble. Measurements are conducted in aqueous ionic-liquid (BMIM) solutions at 0.1%, 1%, 5% and 10% mass concentration, allowing the influence of interface contamination on the lift force to be quantified.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The resulting dataset provides the experimental basis needed to reformulate the drift-flux model for interface-contaminated systems, and supports AURIGA&#8217;s broader aim of connecting local, bubble-scale properties to the global flow regime transitions studied in the theoretical work package.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Within AURIGA&#8217;s bubble-scale work package, Djamel Eddine Aissaoui is characterising the lift force on single bubbles in linear shear flow, using Particle Shadow Velocimetry at HZDR. Single-bubble dynamics are targeted as a key building block for the project&#8217;s broader theoretical aim of modelling flow regime transitions in multi-phase fluid dynamics. Accurate closure models for the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":215,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-248","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/posts\/248","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/comments?post=248"}],"version-history":[{"count":1,"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/posts\/248\/revisions"}],"predecessor-version":[{"id":280,"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/posts\/248\/revisions\/280"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/media\/215"}],"wp:attachment":[{"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/media?parent=248"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/categories?post=248"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.auriga.polimi.it\/index.php\/wp-json\/wp\/v2\/tags?post=248"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}