Project ForgeFluid Mechanics
Flow Through Pipes
GATE 2012
Medium
For the same Couette flow between two parallel plates (bottom plate moving at V, gap b), the force per unit area (in the x-direction) that must be exerted on the bottom plate to maintain the flow is
- μV/b
- B−μV/b
- C2μV/b
- D−2μV/b
Explanation
Shear stress τ=μ|du/dy|=μV/b (constant across the gap, since the velocity profile u=V(1−y/b) is linear). This is the force per unit area that must be applied to the bottom plate to keep it moving against the fluid's viscous drag.
Source: GATE CH 2012 (2012)
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