Question

A fluid is flowing between two layers. Calculate the shearing force if the shear velocity is 0.25 m/s and has length 2 m and dynamic viscosity is 2Ns/m^2.

(a) 0.2 N/m^2

(b) 0.4 N/m^2

(c) 0.5 N/m^2

(d) 0.6 N/m^2

The question was posed to me by my college professor while I was bunking the class.

I would like to ask this question from Factors Affecting Broth Viscosity topic in section Fluid Flow and Mixing of Bioprocess Engineering

Answer 1

Right choice is (c) 0.5 N/m^2

Easiest explanation: Given: Shear velocity u = 0.25 m/s,

shear stress y = 0.125/s

dynamic viscosity μ = 2 Ns/m^2

The shearing stress is given by,

F = μ A u/y

F = 2 Ns/m^2 × 0.125 /s

F = 0.5 N/m^2

Therefore, the shearing stress is 0.5 N/m^2.