In: Mechanical Engineering
A liquid (ρ = 1000 kg/m3; μ = 2 × 10–2 N ∙ s/m2; v = 2 × 10–5 m2/s) flows tangentially past a flat plate with total length of 4 m (parallel to the flow direction), a velocity of 1 m/s, and a width of 1.5 m. What is the skin friction drag (shear force) on one side of the plate?
Given that
ρ = 1000 kg/m3, µ = 2 × 10-2 Ns/m2,
v = 2 × 10-5 m2/s, v = 1m/s
⇒ = Reynolds number
Rex = Vx/υ = 1m/s × 2m/2 × 10-5m2/s = 105.
Rex = 105
⇒ The boundary layer is laminar.
⇒ yRex0.5/x = (0.0008m)(105)0.5/2m = 0.126
Use figure to obtain u/U0
u/U0 ≈ 0.15;
u = 0.15 m/s.
Rex = 105
u = 0.15 m/s.