GUI Work with plotting time v temp

Hello lovely people!

I am attempting to create a code that plots Temperature vs time, the first bit of code on (a) is me doing the math for 50 and 140 temperature. After that is loop where I define the density and viscocity at different temperatures, but it won't do the equation like I wanted to. Any suggestions?

%% GUI #2

volume = 0.0125 % in ft3
D = 0.73/12 % in ft
density = 1.94 % at 50 F
den = 1.91 % at 140 F
vi = 2.73*(10^-5) % for 50 F
visc = 0.974*(10^-5) % for 140 F
 
Vel50 = (2100*vi)/(density*D) % ans in ft/s % velocity at 50 F
Vel140 = (2100*visc)/(den*D)
 
t = (4*volume)/(pi*(D^2)*Vel50) % ans in seconds time at 50 F
t140 = (4*volume)/(pi*(D^2)*Vel140) % ans in seconds
 
% B
Vel5 = (4000*vi)/(density*D) % ans in ft/s
Vel14 = (4000*visc)/(den*D)
 
t = (4*volume)/(pi*(D^2)*Vel5) % ans in seconds
t140 = (4*volume)/(pi*(D^2)*Vel14) % ans in seconds
 
 
% Graph at various water temperatures
dens = [1.940 1.938 1.931 1.908 1.869]; % different densities at temps from chart in book
for k = 1:numel(dens)
    if dens == 1.940
      vi = 3.732*(10^-5)
      disp('Temperature of water is 32 F')
      T = 32;
    elseif dens == 1.938
        vi = 2.344*(10^-5)
        disp('Temperature of water is 60 F')
        T = 60;
    elseif dens == 1.931
        vi = 1.5*(10^-5)
        disp('Temperature of water is 90 F')
        T = 90;
    elseif dens == 1.908
        vi = 9.743*(10^-6)
        disp('Temperature of water is 140 F')
        T = 140;
    elseif dens == 1.869
        vi = 6.342*(10^-6)
        disp('Temperature of water is 200 F')
        T = 200;
    end
    Vel(k) = (2100*vi)/(dens*D)
end
 
for j = 1:numel(Vel)
    tk = (4*volume)/(pi*(D^2)*Vel)
end
 
Tf = [32 60 90 140 200]
plot(Tf,Vel)

Answer 1

[VBBV]

You can change the for loop structure to below and plot time vs emp

for k = 1:numel(dens)
    if dens(k) == 1.940
      vi = 3.732*(10^-5)
      disp('Temperature of water is 32 F')
      T(k) = 32;
      Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    elseif dens(k) == 1.938
        vi = 2.344*(10^-5)
        disp('Temperature of water is 60 F')
        T(k) = 60;
       Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    elseif dens(k) == 1.931
        vi = 1.5*(10^-5)
        disp('Temperature of water is 90 F')
        T(k) = 90;
       Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    elseif dens(k) == 1.908
        vi = 9.743*(10^-6)
        disp('Temperature of water is 140 F')
        T(k) = 140;
        Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    elseif dens(k) == 1.869
        vi = 6.342*(10^-6)
        disp('Temperature of water is 200 F')
        T(k) = 200;
        Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    end    
end

plot(T,Vel,'-b',tk,T,'-r.')
legend('Temp vs Vel','Time vs Temp')

[Walter Roberson]

Caution: if you have an array of literal values like

dens = [1.940 1.938 1.931 1.908 1.869]

and if you compare them with == against the same literal values such as 1.940 ... then MATLAB does not guarantee that they will match.

In theory even if you had

if 1.23456 == 1.23456

then MATLAB does not guarantee that they will match.

In practice, they probably will... but for example if one of them had be save'd in a previous release and pulled back into a newer release, then it might not match.

Better is to never use == between floating point numbers that are not certain to derive from the same source. It is valid, for example, to do something like

   find(x == max(x))

because max(x) guarantees that it copies bit patterns (except for nan... it does not guarantee to preserve identity of nan.)

[kileigh palmer]

When I put that loop into the matlab it worked, but when I did it in the GUI app, it only showed values at T = 32, I attached my modified GUI code below, as well as what the graph is popping up as.

function DiameterinEditFieldValueChanged(app, event)
            D = app.DiameterinEditField.Value/12; % Diameter in ft
           
volume = app.Volumeft3EditField.Value;

% Graph at various water temperatures
dens = [1.940 1.938 1.931 1.908 1.869];
for k = 1:numel(dens)
    if dens(k) == 1.940
      vi = 3.732*(10^-5)
      disp('Temperature of water is 32 F')
      T(k) = 32;
      Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    elseif dens(k) == 1.938
        vi = 2.344*(10^-5)
        disp('Temperature of water is 60 F')
        T(k) = 60;
       Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    elseif dens(k) == 1.931
        vi = 1.5*(10^-5)
        disp('Temperature of water is 90 F')
        T(k) = 90;
       Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    elseif dens(k) == 1.908
        vi = 9.743*(10^-6)
        disp('Temperature of water is 140 F')
        T(k) = 140;
        Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    elseif dens(k) == 1.869
        vi = 6.342*(10^-6)
        disp('Temperature of water is 200 F')
        T(k) = 200;
        Vel(k) = (2100*vi)/(dens(k)*D)
       tk(k) = (4*volume)/(pi*(D^2)*Vel(k))
    end    
end
for k = 1:numel(dens)
    if dens(k) == 1.940
      vi = 3.732*(10^-5)
      disp('Temperature of water is 32 F')
      T(k) = 32;
      Velo(k) = (4000*vi)/(dens(k)*D)
       tkt(k) = (4*volume)/(pi*(D^2)*Velo(k))
    elseif dens(k) == 1.938
        vi = 2.344*(10^-5)
        disp('Temperature of water is 60 F')
        T(k) = 60;
       Velo(k) = (4000*vi)/(dens(k)*D)
       tkt(k) = (4*volume)/(pi*(D^2)*Velo(k))
    elseif dens(k) == 1.931
        vi = 1.5*(10^-5)
        disp('Temperature of water is 90 F')
        T(k) = 90;
       Velo(k) = (4000*vi)/(dens(k)*D)
       tkt(k) = (4*volume)/(pi*(D^2)*Velo(k))
    elseif dens(k) == 1.908
        vi = 9.743*(10^-6)
        disp('Temperature of water is 140 F')
        T(k) = 140;
        Velo(k) = (4000*vi)/(dens(k)*D)
       tkt(k) = (4*volume)/(pi*(D^2)*Velo(k))
    elseif dens(k) == 1.869
        vi = 6.342*(10^-6)
        disp('Temperature of water is 200 F')
        T(k) = 200;
        Velo(k) = (4000*vi)/(dens(k)*D)
       tkt(k) = (4*volume)/(pi*(D^2)*Velo(k))
    end    
end
plot(app.UIAxes,tk,T,'-r.',tkt,T,'-b.')
legend(app.UIAxes,'Time vs Temp: Laminar', 'Time vs Temp: Turbulent')
        end

[VBBV]

Why is the plot showing time on y axis when you are plotting as x axis ? Seems confusing

[VBBV]

Declare T and Velo matrices as below in the beginning before it enters for loop

%true
T = zeros(size(dens));
Velo = zeros(size(dens));
tkt = zeros(size(dens));
dens = [...]; % your values 
for k = 1: length(dens)
 ...
 ...% same as before for rest of code 
end 
plot(app.UIAxes, tkt,T,'-b');
hold(app.UIAxes) 
yyaxis right 
plot(app.UIAxes, Velo, T, '-r')

[kileigh palmer]

I want to plot temperature vs the final times for each temperature. When I did that bit, the graph wasn't plotting the right values, when I tried it with the right x and y values, it still only showed values going along a straight line on the y-axis this time.

T = zeros(size(dens));
Velo = zeros(size(dens));
tkt = zeros(size(dens));
tk = zeros(size(dens));
for k...
end
plot(app.UIAxes,T, tk, '-b');
hold(app.UIAxes)
yyaxis right
plot(app.UIAxes,T,tkt, '-r');

[VBBV]

Use

%f true
delete(app.UIAxes)

In the beginning after function line to delete previous graphs drawn. Since you are using function buttons in GUI to plot, it keeps old plot axes. Next is don't use yyaxis right instead use below

%if true
 plot(app.UIAxes, T, tkt, '-b')
hold(app.UIAxes)
plot(app.UIAxes, T,tk, '-r')

[VBBV]

Also clear the old values

%if true
clear T tk tkt Velo Vel ...

At the beginning of function before assigning zeros to them

[kileigh palmer]

Invalid Handle?

[VBBV]

%f 
delete(handles.app.UIAxes)

Try above

[VBBV]

After the plot function then update the handles GUI

%true
guidata(hObject,handles)

[kileigh palmer]

Unable to resolve the name handles.app.UIAxes

[VBBV]

   %true
    cla reset

Use cla reset option instead of delete(handles.app.UIAxes) in the beginning and try again

[kileigh palmer]

Now its just graphing this:

I also added the most up to date code:

function DiameterinEditFieldValueChanged(app, event)
          cla reset
            D = app.DiameterinEditField.Value/12; % Diameter in ft
           

volume = app.Volumeft3EditField.Value;
clear T tk tkt Velo Vel
dens = [1.940 1.938 1.931 1.908 1.869];
T = zeros(size(dens));
Velo = zeros(size(dens));
tkt = zeros(size(dens));
tk = zeros(size(dens));
% Graph at various water temperatures

for k = 1:numel(dens)
...
    end    
end

plot(app.UIAxes,T, tkt, '-b')
hold(app.UIAxes)

plot(app.UIAxes,T,tk, '-r')

[Walter Roberson]

VBBV: I think they are using App Designer instead of GUIDE.

[VBBV]

Yeah you're right

Answer 2

[Walter Roberson]

    if ismembertol(dens(i), 1.940)

[kileigh palmer]

After that is says Array indices must be positive integers or logical values.

[Walter Roberson]

    if ismembertol(dens(k), 1.940)