How Do You Calculate Reynolds Number for Water Flow in Pipes?

Click For Summary

Discussion Overview

The discussion revolves around the calculation of Reynolds number for water flow in pipes, focusing on the application of the Reynolds number equation in a homework context. Participants explore the implications of unit consistency and the correct use of viscosity in the calculation.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant presents a calculation for Reynolds number using water properties and questions whether the calculation is non-dimensional and if the correct viscosity is used.
  • Another participant provides a comparison between two fluids (water and crude oil) and calculates their respective Reynolds numbers, suggesting that Fluid A is more turbulent than Fluid B based on these calculations.
  • Concerns are raised about the mixing of different units, with a participant noting that the provided pipe size and viscosity are not in SI units.
  • A later reply emphasizes the importance of understanding the formulas and ensuring proper unit usage rather than relying solely on calculations.

Areas of Agreement / Disagreement

Participants express differing views on the correctness of the calculations and the importance of unit consistency. There is no consensus on the resolution of these issues, indicating ongoing debate.

Contextual Notes

Participants have not resolved the implications of using non-SI units in the calculations, and there is uncertainty regarding the appropriate viscosity to use for Reynolds number calculations.

jim1174
Messages
79
Reaction score
0

Homework Statement



Substance water
Temperature 60 degrees c
Density 983kg
Pipe size 10"
Flow rate 10 m/s
Abs viscosity 432 centipoise

Homework Equations





The Attempt at a Solution



(Velocity of fluid or flow rate ) (diameter of pipe) divided by (viscosity of fluid)

(10)(10)(983) divided by (432) = 227.546
 
Physics news on Phys.org
The Reynolds No. is non dimensional. Is your calculation of Reynolds No. non-dimensional? What kind of viscosity is used to calculate Reynolds No.? Have you used the correct viscosity?
 
This is all that was on the assignment

Refer to the Reynolds Number Equation and answer the following questions:
1. Which is more turbulent – Fluid A or Fluid B? Explain your answer?

Fluid a
Substance water
Temperature 60 degrees c
Density 983 kg
Pipe size 10"
Flow rate 10
Abs viscosity 432 centipoise

(10)(10)(983) divided by(432) = 227.546

Fluid b
Substance crude oil
Temp 60 degrees
Density 915kg
Pipe size 10"
Flow rate 10 m/s
Abs viscosity 450 centipoise
(10)(10)(915) divided by 450 = 203.333
 
Last edited:
You are mixing up different units here. If you are working in SI, the pipe size (diameter?) and viscosity given in the question are not in SI units.
 
Like AlephZero stated, you must check these things out. Not all your problems will be simple plug-and-chug calculations. You must think about what the formulas mean and always pay attention to using the proper units.
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
3K
Replies
9
Views
4K
Replies
31
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 15 ·
Replies
15
Views
3K
Replies
15
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
25K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
13
Views
3K