HomeworkSolutions_C6 - Problem #1: A fluid with viscosity...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Problem #1 : A fluid with viscosity 18.3 cp and density 1.32 g/cm3 is flowing in a long horizontal tube of radius 1.05 in (2.67 cm). For what pressure gradient will the flow become turbulent? Answer: The minimum value of Re 4 /( ) wD π µ = needed to produce turbulent flow in a long, smooth tube is about 2100. Poiseuille’s law holds until this critical Re value, giving ( ) 4 0 critical Re<Re 8 L PPR w L πρ = Hence, the pressure gradient needed to initiate the laminar-turbulent transition is () 2 5 44 3 88 4 Re 2100 1.1 10 Pa/km 4 critical dp w D dz R R R µµπ ρ == = Problem #2: Water is flowing through a long, straight, level run of smooth 6.00 in inner diameter pipe, at temperature 68 0 F. The pressure gradient along the length of the pipe is 1 psi/mile. (a) Determine the wall shear stress τ 0 in Pa? (b) Assume the flow to be turbulent and determine the radial distance from the pipe wall at which , using Fig. 5.5-3 in the textbook (second edition), also available in the lecture note. Pay attention at the definition of dimensionless variables.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/01/2011 for the course PGE 312 taught by Professor Peters during the Fall '08 term at University of Texas at Austin.

Page1 / 4

HomeworkSolutions_C6 - Problem #1: A fluid with viscosity...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online