Building the next generation of deformable-impact software
Spectral contact dynamics for drops impacting a bath
Contact is the model
In deformable impact, the contact law can decide the result. I build solvers that move pressure, contact extent, and interface motion from prescribed inputs into the dynamics.
What each model removed
The line began with a rigid sphere and elastic membrane, published in 2022 ((Agüero et al., 2022)). It then made the impactor liquid, then made the target liquid ((Gabbard et al., 2025)). Each transition removed a convenience assumption: fixed impactor shape, rigid target, or prescribed contact.
The solid-substrate branch then isolated non-Newtonian constitutive behaviour. Contact-dynamics work made pressure and contact extent explicit unknowns. Those reductions made clear which assumptions had been carrying the prediction.
Spectral contact dynamics
SpectralKM.jl is the current Newtonian, non-coalescing drop–bath formulation. It represents the bath with Fourier–Bessel modes, the drop with Legendre modes, and contact pressure with shifted-Legendre modes. A feasibility-filtered outer search selects the contact patch.
It removes three choices that can otherwise decide a rebound prediction: a prescribed pressure profile, a mesh-level contact search, and a fixed liquid interface. The bath, drop, pressure supported on the patch, and contact extent are solved together. A disagreement can then be traced to an explicit physical assumption instead of an opaque contact switch.
The pressure inset is diagnostic, not a polished field to over-interpret. Rebound dynamics can settle before a pointwise pressure trace does.
Controlled rheology on a solid
DropRebound.jl isolates how constitutive behaviour changes rebound on a solid substrate. SpectralKM.jl carries the contact problem to two moving liquid interfaces. The videos are separate numerical cases, not a benchmark.
Open source as research infrastructure
Open source is part of the research method here: package code, tests, executable derivations, diagnostics, validation records, parameter sweeps, and rendering scripts live together. A reader can reproduce a result, inspect an assumption, or challenge a conclusion without reconstructing the workflow from a paper.