Desert Dunes: 2D Aeolian Sand Model

Wind and sand

Hop length (wind strength) 5

Wind direction 0 deg

Deposition on sand p_s 0.60

Deposition on bare ground p_ns 0.40

Shadow-zone angle 15 deg

Simulation rate 2000 hops/frame

Initial state

Readouts

Sand grains

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Max height

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Crest lines

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Steepest step

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Migration

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Hops done

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Werner model: pick a sand cell, lift one grain, hop L cells downwind; deposit with p_s on sand (p_ns on bare ground), always in a lee shadow (slope < shadow angle). Slopes steeper than the repose angle avalanche. Barchans and transverse dunes emerge; sand is conserved.