Prof. Joe Alexandersen (University of Southern Denmark) - Topology Optimisation of Fluid Flow and Heat Transfer: Walls, Scales and Time

Please join us on Tuesday, November 17, 2026 for the Pierce Seminar at 4 PM in Room 3-370 with Prof. Joe Alexandersen from the University of Southern Denmark. Abstract Title: Topology Optimisation of Fluid Flow and Heat Transfer: Walls, Scales and Time Abstract: Topology optimisation, originally developed to find stiff and lightweight structures, lets a computer automatically determine where material should, and should not, be placed. Extending it to fluid flow and heat transfer leads to unintuitive designs for flow and cooling systems, but raises fundamental numerical challenges. This talk discusses three of them, with applications in the cooling of electronics and fusion energy devices. First, walls: density-based methods have no explicit surfaces, so physical boundary conditions cannot be imposed on them directly. By extracting wall location and orientation from the design field itself, we impose free-slip conditions and turbulent wall functions implicitly, showing that the boundary physics can change optimal designs dramatically and that accurate turbulent optimisation is possible on coarse meshes. Second, scales: multiscale homogenisation and de-homogenisation produce fine microchannel networks at a fraction of the computational cost. Third, time: treating time as an additional dimension and using parallel space–time multigrid solvers makes transient problems with billions of unknowns tractable. Bio: Joe Alexandersen is an Associate Professor at the University of Southern Denmark (SDU), where he leads the Multiphysics Simulation, Optimisation and Experimentation (MSOE) group at SDU Mechanical Engineering. He received his PhD from the Technical University of Denmark (DTU) in 2016 and was a postdoctoral researcher at DTU before joining SDU in 2019. His research develops topology optimisation methods for fluid flow, heat transfer and multiphysics problems, together with the large-scale and parallel-in-time computational methods needed to make them tractable. He introduced topology optimisation for natural convection and took it to large-scale three-dimensional heat sink design on supercomputers. His group also regularly carries optimised designs through manufacture to experimental testing. Since 2023, he has held a Sapere Aude Research Leader grant from the Independent Research Fund Denmark for the project COMFORT, on computational design for time-dependent problems. His awards include the ISSMO/Springer Prize for Young Scientist and the DTU Young Researcher Award. His review of topology optimisation for fluid-based problems received the Fluids Best Paper Award. He hosts the international TOP Webinar series on topology optimisation.