BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Bruno Blais DTSTART:20260429T070000Z DTEND:20260429T080000Z DTSTAMP:20260424T094527Z UID:MathMAC/60 DESCRIPTION:Title: High-order matrix-free methods for dense particle-laden flows: An open-so urce perspective\nby Bruno Blais as part of Modelling of materials - t heory\, model reduction and efficient numerical methods (UNCE MathMAC)\n\n \nAbstract\nThe simulation of flows using computational fluid dynamics (CF D) has advanced considerably in recent decades and is now an essential too l across industries ranging from aerospace design to process engineering. Although CFD is relatively mature for single-phase flows\, particle-laden flows remain significantly more challenging to simulate\, in part due to t heir intrinsic multiscale nature: particle–fluid interactions at the par ticle length scale propagate across all length scales. Inherently opaque\, these flows are extremely difficult to study experimentally\, and simulat ion remains one of the most viable strategies for gaining insight into the ir internal dynamics. Among the wide variety of simulation models for part icle-laden flows\, Euler–Lagrange approaches are particularly appealing owing to their capacity to describe individual rigid particles explicitly. Two main classes of Euler–Lagrange models can be distinguished: Resolve d (REL) and Unresolved (UREL). Resolved models discretize the fluid equati ons at a scale finer than the particles and enforce the no-slip boundary c ondition at the solid–fluid interface\, typically through an immersed bo undary method. While accurate\, this approach is highly computationally in tensive\, which limits the number of particles that can feasibly be simula ted. Unresolved models instead filter the Navier–Stokes equations and tr eat particles as point momentum sources\, greatly reducing the computation al cost at the expense of requiring accurate closure models. This talk pre sents our efforts in designing Lethe\, an open-source\, high-order multiph ysics framework for single- and multiphase flows built on the deal.II libr ary. We first motivate the use of high-order finite elements for CFD appli cations in process engineering. After discussing the challenges associated with our high-order stabilized formulation\, we introduce matrix-free met hods as a paradigm that alleviates several of these difficulties. We then present the implementation of a matrix-free stabilized Navier–Stokes sol ver within Lethe and demonstrate its capabilities for turbulent flow simul ations. Building on this foundation\, we describe both our REL and UREL im plementations for particle-laden flows and illustrate their capabilities t hrough selected applications. For REL\, we demonstrate the model’s abili ty to accurately capture the dynamics of individual particles by investiga ting the sedimentation of spherical and non-spherical bodies. For UREL\, w e show that this approach can simulate the dynamics of large numbers of pa rticles in complex systems. We conclude by reflecting on the potential of high-order methods for particle-laden flows\, the role of opensource softw are in developing accurate and efficient simulation tools for these comple x systems\, and some of the lessons learned during the development of Leth e. Finally\, we outline future directions for this work\, including the de velopment of more accurate closure models for UREL and the extension of ou r framework to additional multiphysics applications.\n LOCATION:https://researchseminars.org/talk/MathMAC/60/ END:VEVENT END:VCALENDAR