colebrook.py
Current Status: Development
Version: 20190213
TABLE OF CONTENTS
TODO
- Add further approximation functions.
- Add warnings for parameters outside of the range for given formula.
DISCLAIMER
No guarantee of accuracy is provided, confirm results with other sources.
BACKGROUND
The Colebrook-White equation is used to solve for the Darcy Friction Factor (f) for use in the determination of friction losses in pipe and open-channel flows.
The equation is expressed in terms of:
| Parameters | Description |
|---|---|
| Reynolds Number | A dimensionless value that describes the type of flow - As per |
| Pipe Relative Roughness | A value which describes the roughness of the pipe material compared to its inner diameter. |
This module implements various approximations of the function for use in pipe flow calculations.
HOW TO USE
USE AS MODULE
Each approximation takes the Reynolds Number and Relative Roughness as required arguments, with the number of significant figures as an optional argument, in the format of function(reynolds, relative roughness, signficant figures)
For example:
import colebrook
factor = colebrook.sjFriction( 60000, 0.0023)
print(factor)Which outputs
0.027USE AS STAND ALONE APPLICATION
There is also limited ability to run the script from the command line. The script will run against all available functions.
python colebrook.py <reynolds number> <roughness> [Optional Significant figures]
$ python colebrook.py 60000 0.0023
Ensure values are within range of applicability for equations (specifically around transition and laminar region)!
|METHOD | VALUE |
---------------------------
|sjFriction | 0.027 |
|bntFriction | 0.0203 |
|fngFriction | 0.0267 |
|akFriction | 0.0262 |
|bkcFriction | 0.0271 |
|eptFriction | 0.0269 |
DISCLAIMER: Use secondary verification. No guarantee of accuracyCOLEBROOK-WHITE APPROXIMATIONS
The following functions are available in this module. They have been adapted from the Wikipedia Darcy Friction Factor Formulae Table of Approximation page.
| FUNCTIONAME | AUTHOR | YEAR | VALIDITY RANGE | REF |
|---|---|---|---|---|
| sjFriction() | Swamee and Jain | 1976 | Re= 5000 to 10^8 and e/D = 0.00001 - 0.05 | Paper |
| btnFriction() | Bellos, Nalbantis, Tsarkris | 2018 | All Flow Regimes | Paper |
| fngFriction() | Fang et al. | 2011 | R>=2300 | Paper |
| eptFriction() | Evangelides, Papaevangelou, Tzimopoulos | 2010 | R>=2300 | Paper |
| akFriction() | Avci, Kargoz | 2009 | R>=2300 | Paper |
| bkcFriction() | Brkic | 2011 | R>=2300 | Paper |
REVISION HISTORY
| REVISION | DESCRIPTION |
|---|---|
| 20190213 | Initial Development Version |
