Project ForgeFluid Mechanics
Bernoulli's Equation & Flow
GATE 2008
Hard
A moving circular plate descends at uniform speed V towards a stationary surface, squeezing incompressible inviscid fluid out radially. The radial velocity vr at any radius r, when the gap width is h, is
- vr = Vr/2h
- Bvr = Vr/h
- Cvr = 2Vh/r
- Dvr = Vh/r
Explanation
The volume swept out within radius r per unit time (πr²V) must equal the volumetric outflow through the cylindrical surface at radius r (vr·2πrh): vr(2πrh)=Vπr² ⟹ vr=Vr/(2h).
Source: GATE ME 2008 (2008)
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