Home▸Physics & Mechanics▸Granular Hopper Discharge Simulator

⏳ Granular Flow: Why Sand Drains Like a Clock, Not a Liquid

Interactive 3D hopper filled with granular particles where adjusting orifice size and particle friction shows discharge rate staying nearly constant, independent of fill height, unlike a liquid.

Physics & Mechanics3DModerate60 FPS💧 Water 🌍 Earth

A 3D hopper filled with thousands of tumbling grains drains through an adjustable orifice — watch the discharge rate hold nearly steady even as the fill height drops, the same physics that makes an hourglass keep reliable time.

🔬 What It Demonstrates

Grains arch into self-supporting force chains above the orifice, so the weight pressing on the opening stops growing with fill depth. The result: a discharge rate set almost entirely by orifice size and grain size, not head height — unlike a draining liquid.

🎮 How to Use

Shrink the orifice or enlarge the grains to approach a jam; raise friction to make arching and clogging more likely. Watch the live rate chart stay flat while fill height (shown numerically) falls.

💡 Did You Know?

The Beverloo correlation, Q ∝ (D − k·d)^2.5, has been the engineering standard for sizing silo outlets since 1961 — the same principle that keeps hourglasses accurate for hours at a time.

⚙ Under the hood

Interactive 3D hopper filled with sand grains where adjusting outlet width shows why granular flow discharges at a constant rate like a clock instead of a liquid.

granular-flowhopper-dischargebeverloo-equationparticle-physicsjammingphysics

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install