Colebrook-White Equation Calculator

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

    1. Colebrook-White Equation
Rr
Rn

Loops
    1.  
f
    1.  
Left
    1.  
Right
    1.  


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

    Colebrook-White Equation
    [1-5] /5Disp-Num
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    [1]  2014/11/07 02:56   Male / 30 years old level / A teacher / A researcher / Very /
    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?
    [2]  2014/05/09 12:34   Male / 60 years old level or over / An office worker / A public employee / A little /
    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.
    [3]  2013/11/01 03:27   Male / 60 years old level or over / An engineer / Very /
    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.
    [4]  2013/10/04 00:37   Male / 60 years old level or over / A 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.
    [5]  2013/10/02 10:02   Male / 50 years old level / 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))

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