This is a 2D-native companion to the 3D splat simulator — not a flattened camera view. It shows two synchronized panels: a radial cross-section (r–z half-profile, left) and a plan view looking straight down at the substrate (right), which is the natural way to represent an axisymmetric impact in two dimensions.
The impact numbers use the same physics as the 3D model:
Re = ρ·v·D / μ We = ρ·v²·D / σ
ξmax = sqrt( (We+12) / (3(1−cosθ) + 4·We/√Re) )
K = We^0.5 · Re^0.25 (K > ~57 → splashing)
Where this build differs: instead of replaying a scripted animation curve, the splat radius R(t) is obtained by numerically integrating a damped-oscillator ODE each frame,
R'' = −2ζω₀R' − ω₀²(R − Rmax)
with the equilibrium locked to the Pasandideh-Fard ξmax above, but the damping ratio ζ set from ζ ∝ 1/√Re. Low-viscosity (high-Re) impacts come out under-damped and visibly rebound/ring before settling; viscous (low-Re) impacts are over-damped and spread smoothly with no rebound — a real Re-dependent trend the 3D build's canned curve does not reproduce. Splat thickness in the cross-section is recovered from strict cylinder-volume conservation, h(t) = V/(π R(t)²). When K exceeds ~57, satellite droplets are launched as independent 2D ballistic projectiles (their own radial position and simulated flight time, not copied from the 3D particle system) and rendered as an expanding ring of ejecta in the plan view.
- Impact velocity / diameter — raise Re and We together; higher K pushes toward splashing.
- Substrate preheat — improves wetting (raises cosθ), the standard industrial fix for suppressing splashing.
- Material — density, viscosity and surface tension of the molten feedstock set very different Re/We at identical impact speed.