Welcome!
We’re the Computational Physics Group. We build numerical methods, computational models, and open-source software for problems in defense, energy, and medicine — optimized for the world’s largest supercomputers.
Research areas:
2025 Gordon Bell Prize Finalist In August 2025 we ran the largest CFD simulation ever — 1 quadrillion DOFs / 200T grid points on OLCF Frontier and LLNL El Capitan.
Examples of our work
Exascale multiphase flow: Scale-resolving simulation of a multi-rocket-booster configuration via MFC and information geometric regularization (IGR), developed with Florian Schäfer. Record-setting at 1 quadrillion DOFs (200T grid points) on OLCF Frontier (viz. via Ph.D. student Ben Wilfong).
Interested in using MFC?
MFC is our flagship open-source solver for compressible multiphase flow at exascale.
• GPU-optimized for AMD and NVIDIA
• Validated on rocket, cavitation, and bubbly-flow problems
• Actively maintained and used on OLCF Frontier and LLNL El Capitan
Visit the MFC website or the GitHub repo to get started.
Many of the techniques used in our record-setting rocket simulations are available in MFC, so external users can reproduce similar workflows on their own clusters.
Cell-scale flow in microfluidics: High-fidelity spectral boundary integral simulation of blood cells transitioning to chaos. We developed stochastic models enabling microfluidic device design and improved treatment outcomes. Above: a microaneurysm (viz. via student Suzan Manasreh).
News
November 14, 2026
MFC is one of the applications in the SC26 Student Cluster Competition, alongside WRF. Student teams run and tune it on the clusters they build at SC26 in Chicago. Group Ph.D. students Ben Wilfong and Daniel Vickers, with Spencer, presented the competition’s MFC webinar for teams in August.
November 14, 2026
Our paper on diagnosing and delivering repairs for Fortran GPU offload compiler defects appears at the HPCTESTS workshop at SC26, with group Ph.D. students Ben Wilfong and Daniel Vickers. Using MFC as a compiler-validation instrument, three months of testing found 45 defects across the AMD, Cray, and Intel toolchains and produced 18 patches. Alongside it, Spencer launched OffTarget, a catalog of small, legal OpenMP and OpenACC GPU-offload programs that real compilers get wrong on real GPUs, with an offload command that shows which compiler releases support a given clause or construct. Code is on GitHub.
October 31, 2026
Group alum Dr. Anand Radhakrishnan’s paper on a sub-grid-scale model for polydisperse bubbly flows with heat and mass transfer is published in the International Journal of Multiphase Flow. The model closes bubble pressure with heat and mass transfer at the bubble wall in place of a polytropic relation, and is available in MFC.
October 29, 2026
Spencer’s paper on ANEForge, a Python package that programs the Apple Neural Engine directly without CoreML, is published open access in Software: Practice and Experience. It authors optimized computational graphs for arbitrary computation that are submitted directly to the ANE compiler and device.
October 6, 2026
Spencer gives the Oden Institute Seminar on whether high-fidelity flow simulation must stay tied to the largest supercomputers, from the tensor units on datacenter GPUs to the energy-efficient neural accelerators in phones and laptops.
October 3, 2026
The group receives a renewed DOE ALCC allocation of 550K node hours on OLCF Frontier for 2026-27, continuing the Multiphase Mixing Induced by Interface Breakup project with PI Ryan McMullen at Sandia National Labs.
September 25, 2026
Spencer speaks at the Oden Institute’s Babuska Forum on using PDE regularization to sidestep complex numerical treatments in multiphase flow simulation, and on what reduced-precision arithmetic and quantum architectures might offer CFD.
September 3, 2026
Postdoc Dr. Tianyi Chu’s paper on the limits of constant-parameter constitutive models for hydrogels under inertial cavitation is published in Soft Matter. Time-resolved parameter estimation shows where the constant-parameter assumption breaks down during a cavitation event. In collaboration with Michigan.
August 21, 2026
Andrew Wang joins the group as a Ph.D. student in the Oden Institute’s Computational Science, Engineering, and Mathematics (CSEM) program. Welcome, Andrew!
August 15, 2026
The group has moved to UT Austin, where Spencer is Associate Professor in the Walker Department of Mechanical Engineering and Core Faculty in the Oden Institute for Computational Engineering and Sciences. His new email is shb@utexas.edu.
