Consider laminar flow of water over a wide flat plate maintained at a uniform temperature of 50°C, as shown in the figure. The freestream velocity and temperature of water are 1.0 m/s (parallel to the plate) and 20°C, respectively. The distance x from the leading edge, at which the thermal boundary layer thickness δ_T = 0.01 m, is ____ m (rounded off to 1 decimal place). Given: kinematic viscosity ν = 1.0 × 10⁻⁶ m²/s; Prandtl number Pr = 7.01; velocity boundary layer thickness δ_H = 4.91x/√(V_x/ν).

Question

Accepted Answer

The correct answer is 14.8 to 15.6. GATE 2025 official key: 14.8 to 15.6 m. Using δ_H ≈ δ_T·Pr^(1/3) = 0.01×7.01^(1/3) ≈ 0.0191 m, and δ_H = 4.91√x/1000, solving gives x ≈ 15.2 m.