Trying to create a Haaland function to find friction factor inside a loop.

Hello everybody,

I'm trying to find the friction factor to calculate major head loss for 3 different given flow rates for water. I'm a beginner in MATLAB so I couldn't create a function inside my for loop that would calculate 3 different friction factors using Haalands Equation (or Colebrook).

So far the code looks like;

clc; clear all;

% Constants

g = 9.81; % Gravitational acceleration (m/s^2)
rho = 998.23; % Density of water at 20°C (kg/m^3)
D = 25/1000; % Diameter of Galvanized pipe (m)
mu = 1.0016/1000; % Dynamic viscosity of water at 20°C (Pa*s)
K = 0.10; % Minor loss coefficient
epsilon = 0.15; % Roughness coefficient for Galvanized pipe
L = 1.04; % Pipe length (m)
eD = epsilon/D;

Ac = pi*((D^2)/4); % Cross-section area

Vdot = (1000:500:2000)/3600000; % Flow rates (m^3/s)

% Calculations

for i = Vdot
    
    V = Vdot/Ac;
    Re = ((rho*V*D)/mu);
    f  = ???;
    hLminor = K*((V.^2)/(2*g));
    hLmajor = f*(L/D)*((V^2)/(2*g));
    hLtotal = hLmajor + hLminor;
  
end

I have found several examples of Haaland or Colebrook online for matlab but they use "function" which doesn't work in my loop. Any help would be appreciated.

Answer 1

[Cris LaPierre]

See this page on how to create a function.

Functions can be used anywhere in your code, but they must be defined at the bottom of your script. See this page for more details and examples.

If you are new to MATLAB, consider going through MATLAB Onramp to learn the fundamentals.