# Colebrook-White Equation Calculator

## Calculates the root of Colebrook-White Equation using Simple and TRUE method. | ||

The Simple and TRUE method is provided by Harrell Geron as a Federal NRCS, USDA engineer. |

Colebrook-White Equation

[1-5] /5 | Disp-Num |

- Purpose of use
- For teaching purposes:

--> comparison of solution obtained by means of Moody's Diagram and iterative solution of Colebrook - White equation.

--> so that my students can calculate faster the pressure drop in buildings instalations - Comment/Request
- Thanks for the calculator!!

Maybe not too bad, but the solution given for Re < 2000 is not equal to 64/Re. I know it is not necessary to use the Colebrook - White equation in this case, but anyway, it should give an accurate solution, isn't it?

[1] 2014/11/07 02:56 Male / 30 years old level / A teacher / A researcher / Very /

- Purpose of use
- to check manual calculation
- Comment/Request
- please calculate using Colebrook-White equation the

maximum flow capacity & velocity of

pipe size 0.225m. diameter vitrified clay pipe

with gradient of 1/22.

[2] 2014/05/09 12:34 Male / 60 years old level or over / An office worker / A public employee / A little /

- Purpose of use
- If the user selects a mode other that 2.51, then the display of the mode would be good. But it only shows the 2.51 mode.

Also you said you were using 3.71 where I had emailed the "Rr/3.7", but you were using the 3.71 mode.

Today someone asked for the "9.35" mode. and I showed them how, but the screen showed the 2.51 mode, and they wanted to see that equation. - from Keisan
- We have changed to be displayed the formula corresponding to the selected mode.

[3] 2013/11/01 03:27 Male / 60 years old level or over / An engineer / Very /

- Comment/Request
- I tried the Newton compute again, and noticed I could set it for 50 digits like I did.

I did 3 random Rr and Rn and found out that the Newton gets the same answer as I do for 50 digits.

I checked the left and right for each and found they have the same "checked" values also.

I want the Public to learn my easy and true solution, then they could compute their own designs.

[4] 2013/10/04 00:37 Male / 60 years old level or over / A engineer / Very /

- Purpose of use
- The Newton method is fair, but not exactly right.

Here's my easy solution. It works in Excel for 15 digits. Your computer shows 50 digits and it proves I am right. Here's that Rn, and Rr solved

Rn=604133;

Rr=0.01002;

A=Rr/3.7;

B=2.51/Rn;

Loops=0;

D=3; do {X=-2*log(A+B*D);

Loops=Loops+1;

D=-2*log(A+B*X);} while (X<>D);

f=1/X/X;

Left=1/sqrt(f);

Right=-2*log(Rr/3.7+2.51/Rn/sqrt(f));

Loops;

f;

Left;

Right;

10 loops

f= 0.038030096166348760840839356634286786195821313985827

left side of equation '5.1278615179514698534039181406746481344220332448845

right side of equation '5.1278615179514698534039181406746481344220332448845

Left=Right so it is proved right. - Comment/Request
- Post this to everyone

My Excel training is

colebrook-white.blogspot.com

Thanks, Your computer helps me prove I am right. - from Keisan
- We changed Rr/3.7 instead of Rr/3.71 in Colebrook-White Equation.

New results are the same as your results.

1/sqrt(f))=-2*log(Rr/3.7+2.51/Rn/sqrt(f))

[5] 2013/10/02 10:02 Male / 50 years old level / A engineer / Very /

**To improve this 'Colebrook-White Equation Calculator', please fill in questionnaire.**

**The hyperlink to [Colebrook-White Equation]**