Validation of 3D multiphase pyroclastic dilute current model: Effects of confinement on the flows

Validation of 3D multiphase pyroclastic dilute current model: Effects of confinement on the flows | 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 Validation of 3D multiphase pyroclastic dilute current model: Effects of confinement on the flows Shungo Tonoyama, Takashi Nakamura, Gert Lube This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4505870/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The volcanology community started to systematically test numerical models for pyroclastic density currents (PDCs) against benchmarks that are defined through large-scale experiments. Here, we present the results of a three-dimensional LES model for the case of a partially channel-confined, fully dilute, fully turbulent experimental PDC. Our LES model is based on solving the three- dimensional Navier-Stokes equations using a finite-difference method, CIP-CUP scheme. The model results are compared to the experimental benchmark and to the results of a previous validation of a one-dimensional depth-averaged model. To better understand the effect of three dimensionalities of the flow and entrainment of ambient air on flow evolution, we contrast two scenarios: (1) a fully channel-confined simulation, limiting lateral entrainment of air, and representing a three-dimensional scenario of the two-dimensional case, and (2) a partially confined simulation following the set-up geometry of the experimental benchmark. For the first case, the modelling results are similar to those obtained in the depth-averaged simulation, with a close agreement of the position of the flow front against time but showing a more prominent head shape and body height than the physical experiment. In the second case, the front velocity is slightly overpredicting. However, the height of the gravity current nose, the body thickness, and the vertical velocity profiles closely mimic those measured in the experiment. The downstream dilution of the PDCs is significantly enhanced in the partially confined scenario due to the formation of vortexes that laterally spill over the sidewalls, which is also seen in the large-scale experiment. Pyroclastic density current multiphase flow model Entrainment Confinement Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Full Text Additional Declarations Table 1 and 2 are available in the Supplementary Files section. Supplementary Files 20240531TonoyamaNakamuraLubeTab.pdf Cite Share Download PDF Status: Posted Version 1 posted 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-4505870","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":312747884,"identity":"5542bdf8-d00e-4950-9b41-f8cac59c0a28","order_by":0,"name":"Shungo 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