This article investigates matrix-free higher-order discontinuous Galerkin (DG) discretizations of the Navier-Stokes equations for incompressible flows with variable viscosity. The viscosity field may be prescribed analytically or governed by a rheological law, as often found in biomedical or industrial applications. We compare several linearized variants of saddle point block systems and projection-based splitting time integration schemes in terms of their computational performance. Compared to the velocity-pressure block-system for the former, the splitting scheme allows solving a sequence of simple problems such as mass, convection-diffusion and Poisson equations. We investigate under which conditions the improved temporal stability of fully implicit schemes and resulting expensive nonlinear solves outperform the splitting schemes and linearized variants that are stable under hyperbolic time step restrictions. The key aspects of this work are i) the extension of the dual splitting method originally proposed by G.E. Karniadakis et al. (J. Comput. Phys. 97, 414-443, 1991) towards non-constant viscosity, ii) a higher-order DG method for incompressible flows with variable viscosity, iii) accelerated nonlinear solver variants and suitable linearizations adopting a matrix-free $hp$-multigrid solver, and iv) a detailed comparison of the monolithic and projection-based solvers in terms of their (non-)linear solver performance. The presented schemes are evaluated in a series of numerical examples verifying their spatial and temporal accuracy, and the preconditioner performance under increasing viscosity contrasts, while their efficiency is showcased in the backward-facing step benchmark.
When I was in #CS grad school, back in the early 1990s, #wavelets were hot in 3D volumetric CG—oh, those SIGGRAPH symposia on the topic. At the same time in #EE, loads of papers were published on their efficacy in DSP. Just about everyone in EE and CS seemed to have published at least one paper on wavelets. Fun times. But the current state of wavelet academic #research seemed to have dried up.
I don't quite understand why wavelet transform has not supplanted Fourier transform in many #engineering and #computing application domains, considering its estimable time-frequency locality and its prodigious multi-resolution analysis capabilities, compared to Fourier analysis.
I am but a mere "maths carpenter". So, what am I missing, I wonder.
New work:
Distributed Transaction Patterns
https://github.com/ha1tch/dxp/blob/main/README.md
A framework for understanding and implementing distributed transaction patterns through a phase-based spectrum approach.
The DXP documentation is organized as a progressive journey through distributed transaction patterns.
#DistributedSystems #compsci #cloud #cs #foss #golang #natsio #oss #OpenSource
Michael D. Adams is looking for a post-doc to join him in Singapore on a project related to programming with fixed points:
https://michaeldadams.org/hiring/
Should be a fun PL project and a good opportunity to work and live in a cool city. #postdocjob #phd #cs #pl
This article investigates matrix-free higher-order discontinuous Galerkin (DG) discretizations of the Navier-Stokes equations for incompressible flows with variable viscosity. The viscosity field may be prescribed analytically or governed by a rheological law, as often found in biomedical or industrial applications. We compare several linearized variants of saddle point block systems and projection-based splitting time integration schemes in terms of their computational performance. Compared to the velocity-pressure block-system for the former, the splitting scheme allows solving a sequence of simple problems such as mass, convection-diffusion and Poisson equations. We investigate under which conditions the improved temporal stability of fully implicit schemes and resulting expensive nonlinear solves outperform the splitting schemes and linearized variants that are stable under hyperbolic time step restrictions. The key aspects of this work are i) the extension of the dual splitting method originally proposed by G.E. Karniadakis et al. (J. Comput. Phys. 97, 414-443, 1991) towards non-constant viscosity, ii) a higher-order DG method for incompressible flows with variable viscosity, iii) accelerated nonlinear solver variants and suitable linearizations adopting a matrix-free $hp$-multigrid solver, and iv) a detailed comparison of the monolithic and projection-based solvers in terms of their (non-)linear solver performance. The presented schemes are evaluated in a series of numerical examples verifying their spatial and temporal accuracy, and the preconditioner performance under increasing viscosity contrasts, while their efficiency is showcased in the backward-facing step benchmark.
I have long suspected that any language with if's and loops would be Turing complete, turns out there was a proof for that all along...
Olga Carmona de plus en plus proche des Féminines du PSG –
Afin de concurrencer l’Olympique Lyonnais, les Féminines du PSG souhaitent se renforcer. Elles ser…
#Paris #FR #France #Actu #News #Europe #EU #actu #ActuParis #Actualités #ActualitésParis #canalsupporters #Carmona #CS #europe #feminines #FémininesduPSG #fémininespsg #mercato #mercatopsg #NewsParis #OlgaCarmona #ParisNews #parissaint-germain #parissg #psg #psgfeminin #realmadrid #Républiquefrançaise
https://www.europesays.com/fr/183302/
Holy shit can you imagine this seeping into your home and being exposed to it 24/7, even in light amounts?
Walk News
Rxiv mechanobio
amen zwa, esq.
@haitchfive
Jan Midtgaard
Jencel Panic
Paris
@990000@mstdn.social