Consider a steady flow, fully developed flow in a horizontal pipe of diameter D. Over a section of length L of the pipe, a pressure drop of ΔP is observed. Wall stress for the section is _______
1
\(\frac{{{\rm{\Delta }}PD}}{{4L\;}}\)
2
\(\frac{{{\rm{\Delta }}PD}}{{2L\;}}\)
3
\(\frac{{{\rm{\Delta }}P\pi L}}{{2D}}\)
4
\(\frac{{{\rm{\Delta }}P\pi L}}{{4D}}\)