Hello,
I've been trying to finish this code for a few days now. It's quite frustrating since I know exactly what to do but I can't write it in Matlab. I have to find lambda and the Reynolds numbers for the 2 pipes so that I can then calculate the flowrate Q. I need to use an iterative method (using the previous values Matlab calculated to use them in the next loop) but I can't seem to make mine work. My idea is to use a sequence and matlab to loop it until the difference between the previous value of lambdas and the value calculated in the loop is smaller than the tolerance number. I would appreciate it if someone could put me in the right path on how to properly use the iterative method in this case.
The code doesn't work yet because I can't get the lambda values to be close enough yet.
Thank you
clear;clc;% The physical properties
rho = 1000;mu = 1.31e-3;g = 9.81;% The system properties
d1 = 0.1;%input ('Diameter of pipe 1=');
l1 = 2000;%input ('length of pipe 1=');
d2 = 0.05;%input ('Diameter of pipe 2=');
l2 = 100;%input ('length of pipe 2=');
Hc=5; %headloss (45-40m)
A1= (pi*(d1/2)^2/4);A2= (pi*(d2/2)^2/4);tol=10e-6;%tolerance
i=1;% Initial guess of the Reynolds Number
Re1(1)= 2.8e5;for i=1:100 %loop to repeat 100x
lam1(1)= 64/Re1(1); %lambda in pipe 1
V1= sqrt(2*g*d1*Hc/(lam1(1)*l1));% Calculating the velocity in pipe 1 from the Darcy Eq
V2= V1*(A1/A2); %using continuity eq
Re2(1) = rho*(V1*(A1/A2))*d2/mu; %Re in the 2nd pipe
lam2(1)= 64/ Re2(1); %lam2 in 2nd pipe
if lam1(1)-lam2(1)>tol %i'd like to use a while loop that would stop when the 2 lambda values are close enough (tolerance)
Re1(i+1)= rho*V1*d1/mu;Re2(i+1)= rho*V2*d2/mu;lam1= 64/Re1(i+1);lam2= 64/Re2(i+1);else breakend endenddisp ('end')Q1 = V1*pi*d1^2/4;Q2 = V2*pi*d2^2/4;
Best Answer