Industrial scale large eddy simulations (LES) with adaptive octree meshes using immersogeometric analysis

Abstract

We present a variant of the immersed boundary method integrated with octree meshes for highly efficient and accurate Large-Eddy Simulations (LES) of flows around complex geometries. We demonstrate the scalability of the proposed method up to O(32K) processors. This is achieved by (a) rapid in-out tests; (b) adaptive quadrature for an accurate evaluation of forces; (c) tensorized evaluation during matrix assembly. We showcase this method on two non-trivial applications: accurately computing the drag coefficient of a sphere across Reynolds numbers 1 − 10 6 encompassing the drag crisis regime; simulating flow features across a semi-truck for investigating the effect of platooning on efficiency.

A fully-coupled framework for solving Cahn-Hilliard Navier-Stokes equations: Second-order, energy-stable numerical methods on adaptive octree based meshes

“…While this strategy decoupled the implementation challenges of the CH and NS systems, it required multiple matrix assemblies due to the multiple block iterations within each time-step. Xu et al [9], Saurabh et al [10] showed that the matrix assembly and preconditioner setup in a framework such as Khanwale et al [8] can be very expensive.…”

Energy stable and conservative numerical schemes for simulating two-phase flows using Cahn-Hilliard Navier Stokes equations

“…While this strategy decoupled the implementation challenges of the CH and NS systems, it required multiple matrix assemblies due to the multiple block iterations within each time-step. ;Saurabh et al (2020) showed that the matrix assembly and preconditioner setup in a framework such asKhanwale et al (2020) can be very expensive.…”