Stokes Flow (Re → 0)

Creeping flow around a sphere: viscous dominance at low Reynolds number

Radius R: 60

Velocity U: 1.0

Viscosity η: 1.0

Stream function ψ = U r² sin²θ (1 − 3R/2r + R³/2r³). Drag: F = 6πηRU (Stokes law). Compare with potential flow ψ = U r² sin²θ (1 − R²/r²) — no drag paradox (d'Alembert).