Design of a hydraulically confined column device for simultaneous measurement of air relative permeability and water retention in unconsolidated porous media

Design of a hydraulically confined column device for simultaneous measurement of air relative permeability and water retention in unconsolidated porous media | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Design of a hydraulically confined column device for simultaneous measurement of air relative permeability and water retention in unconsolidated porous media Kevin HERNANDEZ-PEREZ, Gerhard SCHÄFER, Amir H. Alizadeh, Mohammad Piri, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9341835/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Air relative permeability is a key parameter controlling gas transport in unsaturated porous media, yet its dependence on saturation history and pore structure remains insufficiently constrained by experimental data. In this study, air relative permeability was measured during controlled drainage and imbibition processes in homogeneous sands with contrasting grain-size distributions. Steady-state air flow experiments were conducted in a laboratory column, and air permeability was determined from imposed gas flow rates and measured pressure gradients. Water saturation was quantified independently from expelled water volumes, allowing reproducible characterization of permeability-saturation relationships along defined hydraulic paths. The results reveal pronounced hysteresis in air relative permeability between drainage and imbibition, with strongly dependent behaviour on grain-size distribution. In the fine sand, air relative permeability decreases progressively with increasing water saturation, whereas in the coarse sand, it remains close to its maximum value over a wide saturation range during imbibition before collapsing abruptly near full saturation. Comparisons with permeability predictions derived from independently fitted water retention curves show significant discrepancies, particularly during imbibition, where saturation-based models fail to reproduce the observed permeability plateau and sharp decline. These findings demonstrate that air relative permeability in granular media cannot be described solely as a function of water saturation and that saturation history and pore structure exert a first-order control on gas transport. The experimental dataset provides a benchmark for evaluating and improving constitutive models for gas flow in unsaturated porous media. Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 04 May, 2026 Reviewers agreed at journal 27 Apr, 2026 Reviewers agreed at journal 20 Apr, 2026 Reviewers invited by journal 20 Apr, 2026 Editor assigned by journal 16 Apr, 2026 Submission checks completed at journal 10 Apr, 2026 First submitted to journal 07 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9341835","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":630402216,"identity":"6831d32c-85ba-4db6-9338-3b73cdba389f","order_by":0,"name":"Kevin HERNANDEZ-PEREZ","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBklEQVRIiWNgGAWjYBACAwjFDOPbwNn8xGpJA7EZG4AsyQYitRwGEfi1mLP3Pnvwc4e1nPzs5mMfPvw5n7idnf3544oaBglzHHose46bG/aeSTdmnHMseeYMntuJO5t5DBvPHGOQkDmAw2E30tgkeNsOJzZL5Bgz80jcTtxwmIexsYGNoU4Cl1/uP2OT/Nt2uL5NIv8z8x+Dc0At7A8bG/4xSODUcoONTRpoSwKPRA4zM0PCAaAWBsPGxjY8Ws6ksUnLtqUbzpA5ZszYcyDZGOgww5mNfRK4tRw/xib5ts1aHhhijxl+/LGT3XD++IOPDd9scGpBAAm8XGK0jIJRMApGwSiAAwBG21dHAj2dagAAAABJRU5ErkJggg==","orcid":"","institution":"University of Strasbourg","correspondingAuthor":true,"prefix":"","firstName":"Kevin","middleName":"","lastName":"HERNANDEZ-PEREZ","suffix":""},{"id":630402217,"identity":"1948512a-e3d2-4caa-95ed-42ecc45f5af9","order_by":1,"name":"Gerhard SCHÄFER","email":"","orcid":"","institution":"University of Strasbourg","correspondingAuthor":false,"prefix":"","firstName":"Gerhard","middleName":"","lastName":"SCHÄFER","suffix":""},{"id":630402218,"identity":"76cbce04-3294-4760-b706-9393d26eb30f","order_by":2,"name":"Amir H. 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