GATE 2024 CH – Question 33
Consider the steady, uni-directional, fully-developed, pressure-driven laminar flow of an incompressible Newtonian fluid through a circular pipe of inner radius 5.0 cm. The magnitude of shear stress at the inner wall of the pipe is 0.1 N m$^{-2}$. At a radial distance of 1.0 cm from the pipe axis, the magnitude of the shear stress, in N m$^{-2}$, rounded off to 3 decimal places, is ______
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Correct answer: 0.010 to 0.030
Explanation
In laminar pipe flow the shear stress varies linearly with the radius, from zero on the axis: $\tau = \tau_w\frac{r}{R} = 0.1 \times \frac{1}{5} = 0.020$ N m⁻².