Question

Using constitutive relations, what is the value of τxxif μ=0.3 and v=4x?

(a) 0.24

(b) 2.4

(c) 0.12

(d) 1.2

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This is a very interesting question from Velocity in division Flows of Viscous Incompressible Fluids of Finite Element Method

Answer 1

Right option is (b) 2.4

Explanation: From constitutive relations, τxx=2μ\(\frac{\partial v_x}{\partial x}\), where μ is the coefficient of viscosity.

\(\frac{\partial v_x}{\partial x}\)

= \(\frac{\partial (4x)}{\partial x}\)

=4.

Thus τxx=2*μ*4.

Given μ=0.3

τxx=2*0.3*4

=2.4.