Question

Determine the specific gravity of a fluid having viscosity 0.07 poise and kinematic viscosity 0.042 stokes.

Answer 1

Specific gravity

$$S(for\ liquids)=\dfrac{\rho_L}{\rho_{H_2O}}$$

Density of water $\rho_{H_2O}=1000kg/m^3$

Given

$\mu_L=0.07\text{ poise}=7\times10^{-3}Ns/m^2,$

$\nu_L=0.042St=4.2\times10^{-6}m^2/s$

Use the relation

$$\nu_L=\dfrac{\mu_L}{\rho_L}$$

Then

$$S=\dfrac{\rho_L}{\rho_{H_2O}}=\dfrac{\mu_L}{\nu_L\cdot\rho_{H_2O}}$$

$$S=\dfrac{7\times10^{-3}Ns/m^2}{4.2\times10^{-6}m^2/s\cdot1000kg/m^3}=\dfrac{5}{3}\approx1.667$$