Blog

Notes from the team on extreme gas dynamics and the technology behind our digital twins.

• When Molecules Spin: A Story of Bulk Viscosity

  9 August 2026 · Torsten Keßler, Michael Abdelmalik, René Hiemstra

  Air is not a gas of billiard balls. Its molecules tumble, and that tumbling makes a gas answer compression on a delay. How we calibrated a collision operator for spinning molecules against measured transport data for nitrogen, carbon monoxide and hydrogen.

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• When Gases Leave Equilibrium: A Story of Approximate Collisions

  4 August 2026 · Torsten Keßler, René Hiemstra, Michael Abdelmalik

  Polynomial entropies make moment closures well-posed but break Boltzmann's entropy bookkeeping. Pairing each entropy with a matching approximate product restores it — and carries a supersonic argon nozzle from near-continuum flow deep into the transitional regime.

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• When Particles Touch: A Story of Fast Tensor Contractions on AI Accelerators

  23 June 2026 · Torsten Keßler, René Hiemstra, Michael Abdelmalik

  How conservation laws collapse an eight-dimensional collision problem into a sparse tensor factorization — and how our GPU kernels turn that structure into 12 TFLOP/s on an Nvidia H200.

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