By analogy with laminar shear, = du/dy. T. V. Bossiness in 1877 postulated that turbulent shear could also be related to the mean-velocity gradient turb

By analogy with laminar shear, τ = μ du/dy. T. V. Bossiness in 1877 postulated that turbulent shear could also be related to the mean-velocity gradient τturb = ε du/dy, where ε is called the eddy viscosity and is much larger than μ. If the logarithmic-overlap law, Eq. (6.28), is valid with τ ≈ τw, show that ε ≈ κρu*y.