Calculates turbulent boundary layer thickness δ ≈ 0.37x/Re_x^0.2 and skin friction coefficient Cf = 0.074/Re_x^0.2 using the 1/5th power law profile. Turbulent BL is thicker but has higher skin friction than laminar — transition from laminar to turbulent occurs at Re ≈ 5 × 10⁵ for a flat plate.
Inputs
U Inf M S
Speed in a specified direction (m/s). Required for momentum, kinetic energy, and wave calculations.
X M
Separation between two points or total path length. Check that units are consistent throughout the calculation.
Nu M2 S
Fluid resistance to flow. Water at 20°C: ~1 cP. Honey: 2,000–10,000 cP. Higher viscosity increases pumping power requirements.
Rho Kg M3
Mass per unit volume (kg/m³). Water: 1,000. Air: 1.225. Steel: 7,850. Affects buoyancy, flow, and structural loads.
Results
turbulent BL thickness δ_turb (mm)
Sample size or count used in the calculation.
local skin friction Cf (turbulent)
Sample size or count used in the calculation.
wall shear stress τ_w (Pa)
Internal force per unit area (Pa or MPa). Must stay below yield strength in service. Beyond yield: permanent deformation. Beyond tensile strength: fracture.