try&erorr
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i want to ask how can i make try&erorr with reasonable erorr the program is 3 tanks have a different energy .. and they connected together by pipe .. this pipe meet togethrt at point j the iteration is to get the energy at j (Ej) .. and then find the flow rate (Q) at each pipe theoretical summtion of Q at j equal 0
this is the program but it has an erorr
clear , clc
fprintf(' \n <<< this program calculate Q in three branched pipes from three tanks >>> \n %12.5f ')
fprintf (' \n 1- Data for highest tank \n %12.5f')
% Data for highest tank
E1=input ('\n Enter tank_ energy (m) : ');
f1=input (' Enter pipe_friction coefficient (m) : ');
d1=input (' Enter pipe_diameter (m) : ');
l1=input (' Enter pipe_length (m) : ');
fprintf (' \n 2- Data for intermediate tank \n %12.5f ')
% Data for intermediate tank
E2=input ('\n Enter tank_ energy (m) : ');
f2=input (' Enter pipe_friction coefficient (m) : ');
d2=input (' Enter pipe_diameter (m) : ');
l2=input (' Enter pipe_length (m) : ');
fprintf (' \n 3- Data for lower tank \n %12.5f ')
% Data for lower tank
E3=input ('\n Enter tank_ energy (m) : ');
f3=input (' Enter pipe_friction coefficient (m) : ');
d3=input (' Enter pipe_diameter (m) : ');
l3=input (' Enter pipe_length (m) : ');
% resistance calculation
R1=(.8*f1*l1)/(9.8*d1^5); % 1st pipe resistance
R2=(.8*f2*l2)/(9.8*d2^5); % 2nd pipe resistance
R3=(.8*f3*l3)/(9.8*d3^5); % 3rd pipe resistance
% junction's energy assumption Ej
Ej=(E1+E3)/2; % E1 <Ej< E3
% Q calculation
Q1=((abs(E1-Ej))/(R1))^.5;
Q2=((abs(E2-Ej))/(R2))^.5;
Q3=((abs(E3-Ej))/(R3))^.5;
if E2<Ej
Qtot=Q1-Q2-Q3;
end
% iteration
if Qtot>0
err=1;
iter=0;
while abs(err)>.001
iter=iter+1;
Ej=Ej+.1;
Q1=((abs(E1-Ej))/(R1))^.5;
Q2=((abs(E2-Ej))/(R2))^.5;
Q3=((abs(E3-Ej))/(R3))^.5;
Qtot=Q1-Q2-Q3;
err=Qtot;
end
end
1 个评论
Jan
2011-11-10
Please use a proper code formatting as explained at the "Markup help" link. Currently your code is not readable.
回答(1 个)
Walter Roberson
2011-11-10
It isn't clear to me that the required error tolerance is certain to be satisfied when Ej is incremented by a constant value. Shouldn't you be doing some zero-crossing detection to zero in on proper Ej ? You could arrange it as an fzero or fmincon optimization.
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