Blasius Boundary Layer — Flat Plate Viscous Flow

〰 Blasius Boundary Layer

Freestream U∞ 5.0 m/s Plate length L 0.5 m Kinematic viscosity ν

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Re_L

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δ₉₉ at x=L (mm)

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C̄_f (avg)

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τ_w at x=L (Pa)

Blasius (1908) solved f‴ + ½ff″ = 0 analytically for laminar flow over a flat plate. The boundary layer thickness grows as δ₉₉ ≈ 5.0√(νx/U∞), and skin friction C_f = 0.664/√Re_x. Profiles self-similar when plotted vs η = y√(U∞/νx).

Colour guide: orange fill = boundary layer region, white curves = velocity profiles u/U∞ at 4 stations, arrows = freestream, plate at bottom.