GATE 2016 ME (ME1) – Question 54
A fluid with Pr = 1 at 500 K flows at 10 m/s over a 1.5 m plate maintained at 300 K. Given kinematic viscosity $\nu=30\times10^{-6}$ m²/s, the thermal boundary-layer thickness 0.5 m from the leading edge is ______ mm.
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Correct answer: 5.90 to 6.25
Explanation
At x=0.5m, Rex=Ux/ν=10·0.5/(30e−6)=166667, consistent with a laminar flat-plate layer. The approximate thickness isδ≈5x/sqrtRex=0.006124m. With Pr=1, thermal and velocity thicknesses are equal. Thus **δt≈6.124mm**.