Question: A thin plate of length 1.0 m is held in a uniform air flow such that its length is parallel to the flow direction. The flow speed is 25 m/s, the viscosity, µ = 14.96 × 10-6 Pa/s, and the air density, 1.203 kg/m3.
(a) If it is known that transition from laminar to turbulent flow occurs when the Reynolds number based on x reaches 500,000, find the transition point.
(b) Calculate the equivalent plate length for an all-turbulent boundary layer with the same momentum thickness at the trailing edge as at the actual boundary layer.
(c) Calculate the coefficient of skin-friction drag per unit breadth for that part of the plate with
• A laminar boundary layer
• A turbulent boundary layer (Use the formulas based on the one-seventh-power-law velocity pro- file.) (d) Calculate the total drag per unit breadth.
(e) Estimate the percentage of drag due to the turbulent boundary layer alone