How create a interaction method to re-calculate a equation if a condition is not satisfied

I have a equation where i need to input a value and calculate some equations with this value.

In the end, i need to check if this value is ok.

If it's not, I need to input a new value and calculate the equation again with this new value.

Somebody can help me?

I tried this way.

I need to input "Tin" and calculate "Tw". In the end, i need check if the average between Tw and "Tb" in less than 10%. If it's not i neet to input a new value for "Tave".

    clear
    close all

    Tin=input('Input T');       

    D=5;                     
    t=0.362;                 
    E=2.9e07;                
    ws=17.9148297590378;  
    R=1448.88;               
    alfa=1.96;      

    h=R*(1-(cos(alfa/2)));   
    I=pi*(D-t)*(D-t)*(D-t)*t/8; 
    teta=19.45;   
    L=495.73;          
    conv=teta*pi/180;          
    mis=0.3;   
    mil=0.05;                  
    DRAG= 12*pi*D*L*mil;   

    Tb=8.89e4;

    G=Tin;

    for i=1:100
      G(i)=Tin(i);
      J=sqrt(E*I/G(i));
      U=12*L/J;
      X=3*L-(J/2)*tanh(U/2);
      Y=18*L*L-J*J*(1-(1/cos(U/2)));
      N=(12*G(i)*h-(ws/12)*cos(teta)*Y)/X;  
      frictc=N*mis;
      ter=ws*L*sin(conv);
      deltac=2*frictc+DRAG-ter;   

      Tw=deltac+Tb;

      Tave(i)=(Tw+Tb)/2;

      if Tave(i)>G(i)+G(i)*0.1
        G(i)=Tave(i);
       elseif Tave2(i)<G(i)-G(i)*0.1
            G(i)=Tave2(i);
        else
            display(Tave2(i));
        end
    end

[sixwwwwww]

you have to enter new value for Tave or Tin? and also what is meaning of it " i need check if the average between Tw and "Tb" in less than 10%" less than 10% of which values ?

[Gabriel]

I'm sorry

New value for "Tin" if "Tave" is greater than 10% of "Tin".

Now the sentence is correct

Answer 1

[sixwwwwww]

try this:

Tin=input('Input T');
D=5;
t=0.362;
E=2.9e07;
ws=17.9148297590378;
R=1448.88;
alfa=1.96;
h=R*(1-(cos(alfa/2)));
I=pi*(D-t)*(D-t)*(D-t)*t/8;
teta=19.45;
L=495.73;
conv=teta*pi/180;
mis=0.3;
mil=0.05;
DRAG= 12*pi*D*L*mil;
Tb=8.89e4;
G(1) = Tin;
for i=1:100    
    J=sqrt(E*I/G(i));
    U=12*L/J;
    X=3*L-(J/2)*tanh(U/2);
    Y=18*L*L-J*J*(1-(1/cos(U/2)));
    N=(12*G(i)*h-(ws/12)*cos(teta)*Y)/X;
    frictc=N*mis;
    ter=ws*L*sin(conv);
    deltac=2*frictc+DRAG-ter;
    Tw=deltac+Tb;
    Tave(i)=(Tw+Tb)/2;
    if Tave(i) >= Tin * 0.1
        Tave(i) = input('Enter new value of Tave:');
    end
    G(i + 1) = Tave(i);                
end
display(Tave(i))

[Gabriel]

I think it works well

But now i see, that i need to use the value of "Tave" as the new "Tin" if the condition is not satisfied.

Or display the value of "Tave" if he is grather than 10%

[sixwwwwww]

try now:

Tin=input('Input T');
D=5;
t=0.362;
E=2.9e07;
ws=17.9148297590378;
R=1448.88;
alfa=1.96;
h=R*(1-(cos(alfa/2)));
I=pi*(D-t)*(D-t)*(D-t)*t/8;
teta=19.45;
L=495.73;
conv=teta*pi/180;
mis=0.3;
mil=0.05;
DRAG= 12*pi*D*L*mil;
Tb=8.89e4;
G(1) = Tin;
for i=1:100    
    J=sqrt(E*I/G(i));
    U=12*L/J;
    X=3*L-(J/2)*tanh(U/2);
    Y=18*L*L-J*J*(1-(1/cos(U/2)));
    N=(12*G(i)*h-(ws/12)*cos(teta)*Y)/X;
    frictc=N*mis;
    ter=ws*L*sin(conv);
    deltac=2*frictc+DRAG-ter;
    Tw=deltac+Tb;
    Tave(i)=(Tw+Tb)/2;
    if Tave(i) >= Tin * 0.1
        Tave(i) = input('Enter new value of Tave:');
        Tin = Tave(i);
        G(i + 1) = Tin;
    else
        display(Tave(i))
    end
end

[Gabriel]

This way its continue to ask me a new value for Tave and I dont have idea of wich value is good to input

[sixwwwwww]

maybe it will be better if you view value and then next value which can make Tave less then 10% of Tin.

    Tave(i)=(Tw+Tb)/2;
    if Tave(i) >= Tin * 0.1
        display(Tave(i));
        Tave(i) = input('Enter new value of Tave:');
        Tin = Tave(i);
        G(i + 1) = Tin;
    else
        display(Tave(i))
    end

Try this way. Also I have no idea which values you should input for this purpose hahaha. So this idea you should think by yourself

[Gabriel]

I'm sorry the newbie ask, but in this programa the value of Tw is being changing every time that Tave changes, isn't it?

[sixwwwwww]

Yes value of Tw is changing in each for loop iteration and so Tave also changes each time

Answer 2

[Walter Roberson]

need_to_continue = true;

while need_to_continue
  Tin = input('Temperature In');
  ....
  need_to_continue = (Tw + Tb)/2 > Tb/10;   %average is more than 10% ?
end

Answer 3

[Gabriel]

Thanks so much..

It's running perfectly now...

[sixwwwwww]

you are welcome