- What are X_0 and phi_0 ?
- I don't see cos(phi_j+1 - phi_j), cos(phi_j - phi_j-1), sin(phi_j+1 - phi_j), sin(phi_j - phi_j-1) in your code.
- y(16) - y(20) must be calculated after you get back y(1) - y(15) from ODE45. They are not part of the system of differential equations.
is my program for solving differential equation is correct or not?
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to solve this couple differential equation i wrote a program,
Z1....Z5 is y(1)...y(5), X1...X5 is y(6).......y(10) and Φ1.......Φ5 is y(11).....y(15)
hence I want to sovle another equation which is
Φ2 - Φ1 = y(16)
Φ3 - Φ2 = y(17)
Φ4 - Φ3 = y(18)
Φ5 - Φ4 = y(19)
Φ1 - Φ5 = y(20)
while solving these equation I didn't ge any fluctuation in the graph is my program correct or not?
clc
ti = 0;
tf = 70E-9;
tspan=[ti tf];
tp =1E-12;
T = 2E3;
P = 0.05;
k = (0.62).*10^(0);
c = 3E8;
N = 3;
n = k*(c/N)*tp
a = 3;
f = @(t,y) [
(P - y(1) - ((2.*y(1) +1).*(((y(6)))^2)))./T;
(P - y(2) - ((2.*y(2) +1).*(((y(7)))^2)))./T;
(P - y(3) - ((2.*y(3) +1).*(((y(8)))^2)))./T;
(P - y(4) - ((2.*y(4) +1).*(((y(9)))^2)))./T;
(P - y(5) - ((2.*y(5) +1).*(((y(10)))^2)))./T;
(y(1).*y(6)) - n.*(y(7).*sin(y(12) - y(11)) + y(10).*sin(y(15)- y(11)));
(y(2).*y(7)) - n.*(y(8).*sin(y(13) - y(12)) + y(6).*sin(y(11) - y(12)));
(y(3).*y(8)) - n.*(y(9).*sin(y(14) - y(13)) + y(7).*sin(y(12) - y(13)));
(y(4).*y(9)) - n.*(y(10).*sin(y(15) - y(14)) + y(8).*sin(y(13) - y(14)));
(y(5).*y(10)) - n.*(y(6).*sin(y(11) - y(15)) + y(9).*sin(y(14) - y(15)));
-a.*(y(1))+ n.*((y(7)./y(6)).*(cos(y(12) - y(11))) + (y(10)/y(6)).*(cos(y(15) - y(11))));
-a.*(y(2))+ n.*((y(8)./y(7)).*(cos(y(13) - y(12))) + (y(6)/y(7)).*(cos(y(11) - y(12))));
-a.*(y(3))+ n.*((y(9)./y(8)).*(cos(y(14) - y(13))) + (y(7)/y(8)).*(cos(y(12) - y(13))));
-a.*(y(4))+ n.*((y(10)./y(9)).*(cos(y(15) - y(14))) + (y(8)/y(9)).*(cos(y(13) -y(14))));
-a.*(y(5))+ n.*((y(6)./y(10)).*(cos(y(11) - y(15))) + (y(9)/y(10)).*(cos(y(14) - y(15))));
y(12) - y(11);
y(13) - y(12);
y(14) - y(13);
y(15) - y(14);
y(11) - y(15);
];
y0=[0; 0; 0; 0; 0; 0.6; 0.6; 0.6 ; 0.6; 0.6; 0; 0; 0; 0; 0; 0; 0; 0; 0; 0]*10E-3;
[time,Y] = ode45(f,tspan./tp,y0);
plot(time,Y(:,16));
hold on
plot(time,Y(:,18));
plot(time,Y(:,17));
plot(time,Y(:,19));
plot(time,Y(:,20));
hold off
3 Comments
Torsten
on 3 Sep 2022
Edited: Torsten
on 3 Sep 2022
your third point, I don't know how to do that please tell me.
Remove y(16) up to y(20) from the function for the differential equation and use
hold on
plot(time,Y(:,12)-Y(:,11))
plot(time,Y(:,13)-Y(:,12))
plot(time,Y(:,14)-Y(:,13))
plot(time,Y(:,15)-Y(:,14))
plot(time,Y(:,11)-Y(:,15))
hold off
instead of
plot(time,Y(:,16));
hold on
plot(time,Y(:,18));
plot(time,Y(:,17));
plot(time,Y(:,19));
plot(time,Y(:,20));
hold off
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