Chapter 5, Problem 5.4P

Interpretation Introduction

Interpretation: The power per meter of width between 2 horizontal flat plates is to be calculated for the lubricating oil.

Concept introduction: The power required per meter of width of flat plates is the product of the pressure drop between the plates and the flow rate of the oil.

  $\text{P}\text{=}{\text{(p}}_{\text{a}}\text{-}{\text{p}}_{\text{b}}\text{)}\text{×}\text{q}\mathrm{.......}\text{(1)}$

P is the power required

q is the flow rate of the oil per meter of the width

  ${\text{p}}_{\text{a}}\text{-}{\text{p}}_{\text{b}}\text{=}\text{Pressure}\text{drop}\text{across}\text{plates}$

The pressure drop across the plates is given as,

  

The notations used here are,

  

The average velocity here is given as,