Barrel Explosion — Blast Overpressure & Fragment Scatter (2D)

Charge

Charge mass (TNT-equiv) 20 kg

Observer

Distance from barrel 6.0 m

Hazard at observer

SAFE — BELOW GLASS-DAMAGE THRESHOLD

Live Readouts

Peak overpressure

—

Scaled distance Z

—

Severe-damage radius

—

Fragment velocity

—

How this differs from the 3D view

The 3D version is a click-to-chain-react barrel field with a fixed-radius trigger — it doesn't compute an actual pressure field. This 2D companion instead solves the real empirical blast-scaling laws used in explosion-safety engineering, driven by the same two physical quantities (charge mass, distance):

Z = R / W^(1/3)                                     (Hopkinson-Cranz cube-root scaling)
Pso(kPa) = 1772/Z − 114/Z² + 108/Z³                 (Kingery-Bulmash curve fit)
V0 = √(2·Eg) · √[(C/M) / (1 + C/2M)]                (Gurney equation, fragment velocity)

Doubling the charge mass W does not double the blast radius — because overpressure scales with the cube root of energy, an 8× heavier charge is needed to double the reach of a given overpressure level. The animated shock ring's radius follows a decelerating R(t) ∝ t^(2/5) law (Sedov-Taylor point-blast scaling) rather than moving at constant speed. Fragment ejection speed uses the Gurney equation with a fixed charge-to-metal ratio typical of a steel drum (C/M ≈ 1) — note it does not depend on the absolute charge mass, only on that ratio, which is why heavier charges make a bigger, more damaging blast without necessarily throwing shrapnel faster.

Top panel — top-down view: the barrel, the expanding shock ring (colour = local overpressure), decelerating shrapnel fragments, and your observer marker at the chosen distance.
Bottom panel — peak overpressure vs. distance for this charge mass, on a log-log curve, with your observer distance marked and standard hazard thresholds shown as horizontal guides.

Shock front Fragments Observer