A fluid is flowing over a flat plate. At a distance of 10 cm from
| A fluid is flowing over a flat plate. At a distance of 10 cm from the leading edge, the Reynolds number is found to be 3200000. The thickness of the boundary layer at this point is
A. 1.89 mm
B. 2.89 mm
C. 1.69 mm
D. 2.69 mm
Please scroll down to see the correct answer and solution guide.
Right Answer is: A
SOLUTION
Concept:
The thickness of the boundary layer is given by \(\delta = \frac{{5x}}{{\sqrt {R{e_x}} }}\)
For turbulent flow \(\delta = \frac{{0.379\;x}}{{R{e^{\frac{1}{5}}}}}\)
Where δ = Boundary layer thickness, x = Distance of boundary layer from the leading edge, Rex = Reynold’s number at the distance x from the leading edge
Calculation:
Since in this given case, Reynold’s number is 3200000 which is in the range of 5 × 105 to 107, so the flow is turbulent.
Given, x = 10 cm = 0.1 m
∴ \(\delta = \frac{{0.379\;x}}{{R{e^{\frac{1}{5}}}}} = \frac{{0.379\;\times 0.1}}{{3200000^{\frac{1}{5}}}}=1.895 \; mm \)