A fluid near a solid wall has an approximated velocity profile given by \(u\left( y \right) = \;{U_\infty } \times \sin \left( {\frac{{\pi y}}{{2\delta }}} \right),\;0 \le y \le \delta \) . The walls shear stress is given by:
1
\({\tau _{wall}} = \;\frac{{\pi \mu {U_\infty }}}{{2\delta }}\)
2
\({\tau _{wall}} = \;\frac{{3\pi \mu {U_\infty }}}{{\delta }}\)
3
\({\tau _{wall}} = \;\frac{{2\pi \mu {U_\infty }}}{{\delta }}\)
4
\({\tau _{wall}} = \;\frac{{\pi \mu {U_\infty }}}{{\delta }}\)