Sofia Demo Reel

Abstract

A showcase of simulations written with Sofia, each for a different physics domain. Each example is verified against a reference: either an exact solution, a textbook reference, or a conserved total.

Fermioniq·8 October 2026·5 cases

Laptop CPUfree_surface · 2D shallow water

The Waal at Nijmegen

7,000 particles carried by the steady flow of the river Waal at high discharge, over aerial imagery. The main channel runs fastest past Nijmegen; slower sheets of water cross the flooded floodplains inside the meanders. One second of video is ten minutes of river time.

Checked The validated 50 m rerun, compared with Deltares’ D-Flow FM elsewhere; Q = 10,165 m³/s

NVIDIA GH200lattice_boltzmann · D3Q19 LES

Wind through Amsterdam Science Park

A south-westerly wind through the real campus, built from the 3D BAG building heights and seen from above the south-east, with the wind running left to right. The wind speed 9 m above the...

Checked Collision self-check: 3D Taylor–Green viscosity to 0.5%, float64 and float32; smoke run finite, peak Mach 0.12, mass drift 9e-5

NVIDIA GH200incompressible_flow · LES

Flow around the Ahmed body

Wind over an Ahmed body, the standard car-aerodynamics test shape, here the AhmedML variant with a steep 61° rear slant. Threads of smoke from 65 nozzles ahead of the nose ride the simulated wind,...

Checked Drag coefficient 0.231 over the last 8 s, against the AhmedML reference 0.238 (−3%)

NVIDIA GH200thermal · conjugate heat transfer + gradient descent

Heat-sink design by gradient descent

Gradient descent walks 20 parameters of a pin-fin heat sink downhill: each row’s pin diameter, height and offset, and the two pitches. It took 13 steps on a 0.5 mm grid; the 40 designs...

Checked Energy balance: the heat leaving through the outlet is 4.96–4.99 W of the 5 W input in every design. Grid check: the objective falls 21% on the 0.5 mm grid and 23% when the same designs are re-solved at 0.25 mm

NVIDIA GH200acoustics · linear acoustics, 3D

The whispering gallery of St Paul's

A whisper at the wall of St Paul’s whispering gallery, 30 m above the cathedral floor. It creeps round the wall both ways, and the two halves meet at a listener on the far...

Checked Echo arrival times 0.19, 0.29, 0.59 and 0.89 s against the measured ~0.2, 0.3, 0.6 and 0.9 s (Foteinou, Stevens & Murphy, Acoustics 7(3):49, 2025). The solver beforehand: in 2D against the exact solution for a rigid circle; in 3D against the BRAS RS8 curved-reflector measurements (TU Berlin), focal level within 1 dB from 500 Hz to 4 kHz