JEE Main · 2022 · 26 Jun 2022 · Shift 2 · Fluid Mechanics

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ρ

is the density and

η

is coefficient of viscosity of fluid which flows with a speed v in the pipe of diameter d, the correct formula for Reynolds number

R_{e}

is :

(A) $R_{e} = \frac{η d}{ρ v}$
(B) $R_{e} = \frac{ρ v}{η d}$
(C) $R_{e} = \frac{ρ v d}{η}$ ✓ Correct
(D) $R_{e} = \frac{η}{ρ v d}$

Answer: (C)

Solution

The Reynolds number is a dimensionless quantity that characterizes the flow regime of a fluid. It is defined as

R_{e} = \frac{ρ v d}{η}

, where

ρ

is the fluid density,

v

is the flow speed,

d

is the characteristic length (pipe diameter), and

η

is the coefficient of viscosity.

JEE Main · 2022 · 26 Jun 2022 · Shift 2 · Single correct option

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