Show that the Reynolds number is dimensionless.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
The formula for the Reynolds number $(R_{e})$ is given by: $R_{e} = \frac{\rho v d}{\eta}$
Where:
$\rho$ (density) = $[M^{1} L^{-3} T^{0}]$
$v$ (velocity) = $[M^{0} L^{1} T^{-1}]$
$d$ (diameter) = $[L^{1}]$
$\eta$ (coefficient of viscosity) = $[M^{1} L^{-1} T^{-1}]$
Substituting the dimensions into the formula:
$R_{e} = \frac{[M^{1} L^{-3} T^{0}] [M^{1} L^{1} T^{-1}] [L^{1}]}{[M^{1} L^{-1} T^{-1}]}$
$R_{e} = \frac{[M^{1} L^{-1} T^{-1}]}{[M^{1} L^{-1} T^{-1}]}$
$R_{e} = [M^{0} L^{0} T^{0}]$
Since all the powers of the fundamental dimensions are zero,the Reynolds number is dimensionless.

Explore More

Similar Questions

The rate of steady volume flow of water through a capillary tube of length $l$ and radius $r$,under a pressure difference of $p$ is $V$. This tube is connected with another tube of the same length but half the radius,in series. Then,the rate of steady volume flow through them is (The pressure difference across the combination is $p$.)

What is the value of the Reynolds number $(R_e)$ for unsteady flow?

$Assertion :$ For Reynolds number $Re > 2000$, the flow of fluid is turbulent.
$Reason :$ Inertial forces are dominant compared to the viscous forces at such high Reynolds numbers.

$A$ capillary tube is connected to the bottom of a container. If its radius is increased by $10\%$,what is the percentage change in the rate of flow of the liquid (in $\%$)?

Water from a pipe is coming at a rate of $100\, L/min$. If the radius of the pipe is $5\, cm$, the Reynolds number for the flow is of the order of: (density of water $= 1000\, kg/m^3$, coefficient of viscosity of water $= 1\, mPa\, s$)

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo