MATLAB Answers

Water Tank input that changes based on volume.

21 views (last 30 days)
Need to plot the volume of water and concentration of pollutant in a tank of water. Initial inflow is 1.25 m^3/s, and outflow is 1.1. When the tank's volume reaches 200 m^3, the inflow is 0, and returns to 1.25 when the volume drops to 150. How can inflow (Qin) be changed to 0 at V=200, and then reset at V=150? if statement?
Here is code for a prior part to the project that assumes a constant rate of fill:
V0 = 50; %initial volume (m^3)
c0 = 0; %initial concentration
Qin = 1.25 * 60; %inflow (m^3/hour)
Qout = 1.1 * 60; %outflow (m^3/hour)
cin = 100; %pollutant concentration (mg/L)
t_final = 50; %hours
dt = 0.5; %time step
T = [dt:0.5:50];
t = 0;
%
k = 0;
%
%Initialize Loop Variables
cold = c0;
vold = V0;
for n = [1 : (t_final/dt)];
t = t + dt;
k = 0;
alpha = (Qin / (vold + (Qin - Qout) * t)) + k;
beta = (Qin*cin)/(vold+(Qin - Qout) * t);
c(n) = cold - dt * alpha * cold + dt * beta;
V(n) = vold + (Qin - Qout) * dt;
cold = c(n);
vold = V(n);
end
yyaxis left
plot(T,V)
ylabel('Volume (m^3)')
xlabel('Time (hours)')
yyaxis right
plot(T,c)
ylabel('Concentration (mg/L)')
disp(' t V c')
format compact
disp([T' V' c'])
more(10)

  0 Comments

Sign in to comment.

Accepted Answer

Subhamoy Saha
Subhamoy Saha on 12 Mar 2020
Please check with the following
clear, clc
V0 = 50; %initial volume (m^3)
c0 = 0; %initial concentration
Qin = 1.25 * 60; %inflow (m^3/hour)
Qout = 1.1 * 60; %outflow (m^3/hour)
cin = 100; %pollutant concentration (mg/L)
t_final = 50; %hours
dt = 0.5; %time step
T = [dt:0.5:50];
t = 0;
%
k = 0;
%
%Initialize Loop Variables
cold = c0;
vold = V0;
inflow=1; % inflow status variable
for n = [1 : (t_final/dt)]
t = t + dt;
k = 0;
if vold>=200 || inflow==0
inflow=0; % say inflow stopped
if vold<=150
inflow=1; % say inflow start
end
end
if inflow==0
Qin=0;
else
Qin=1.25 *60;
end
alpha = (Qin / (vold + (Qin - Qout) * t)) + k;
beta = (Qin*cin)/(vold+(Qin - Qout) * t);
c(n) = cold - dt * alpha * cold + dt * beta;
V(n) = vold + (Qin - Qout) * dt;
cold = c(n);
vold = V(n);
end
yyaxis left
plot(T,V)
ylabel('Volume (m^3)')
xlabel('Time (hours)')
yyaxis right
plot(T,c)
ylabel('Concentration (mg/L)')
disp('      t        V           c')
format compact
disp([T' V' c'])
more(10)

  1 Comment

Karl Nilsson
Karl Nilsson on 12 Mar 2020
Thanks. I figured it out eventually but this is much more efficient.

Sign in to comment.

More Answers (0)

Products


Release

R2019b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!