The rate of rotation of fluid particle is given by

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Direction: The laminar row takes place between closely spaced parallel plates as shown in figure below. The velocity profile is given by
u = V = v/h. The gap height, h is 5 mm and the space is filled with oil (specific gravity = 0.86, viscosity m = 2 × 10^–1 N-s/m²). The bottom plate is stationary and the top plate moves with a steady velocity of V = 5 cm/s. The area of the plate is 0.25 m².

The rate of rotation of fluid particle is given by

1. ω_y = 0; ω_z = −v
  2h
2. ω_y = 0; ω_z = − v
  h
3. ω_y = v ; ω_z = v
  h h
4. ω_y = v ; ω_z = 0
  h

Correct Option: A

u = V		y
		h

V = 0, ω = 0
Condition for rotation flow of laminar fluid

ω_y =	1		∂u	−	∂ω		= 0
	2		∂z		∂x

ω_z =	1		∂V	−	∂u
	2		∂x		∂y

=	1		0 −	∂		V.	y
	2			∂y			h

=	1		−	V
	2			h

= −	V
	2h