colebrook 0.0.5

A small module that calculate colebrook-white approximations

colebrook.py

Current Status: Development

Version: 20190213

TABLE OF CONTENTS

• colebrook.py
• TABLE OF CONTENTS
  • TODO
  • DISCLAIMER
  • BACKGROUND
  • HOW TO USE
    • USE AS MODULE
    • USE AS STAND ALONE APPLICATION
  • COLEBROOK-WHITE APPROXIMATIONS
  • REVISION HISTORY

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

    0.027

USE 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 accuracy

COLEBROOK-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