How to run ode15s function for several times

조회 수: 3 (최근 30일)
tamara hussien
tamara hussien 2017년 11월 13일
댓글: Steven Lord 2017년 11월 14일
Thanks for taking the time to read this, I am new to matlab. The following four equations are what I need to solve them by ode15s:
eq1=diff(uc(t),2)==(-1/(L*(3*mc+4*h2*L*pi*a2*Ro)))*(3*(-Ft*L+4*h2*pi*a11*a2*(uc(t)+Beta*diff(uc(t)))+L*(alfa*mc*diff(uc(t))+pi*(p2(t)*a2^(2)-p1(t)*a2^(2)+2*h2*a12*(wr1(t)-wr2(t)+Beta*diff(wr1(t))-Beta*diff(wr2(t))))))+4*pi*h2*L^(2)*a2*alfa*Ro*diff(uc(t)));
eq2=(h2*L*a2^(2)*Ro)*diff(wr1(t),2)==(-h2*a12*a2*(uc(t)+Beta*diff(uc(t)))+L*(a2^(2)*p1(t)-h2*a22*(wr1(t)+Beta*diff(wr1(t))))-h2*L*a2^(2)*alfa*Ro*diff(wr1(t)));
eq3=(h2*L*a2^(2)*Ro)*diff(wr2(t),2)==(h2*a12*a2*(uc(t)+Beta*diff(uc(t))+L*(a2^(2)*p2(t)-h2*a22*(wr2(t)+Beta*diff(wr2(t)))))-h2*L*a2^(2)*alfa*Ro*diff(wr2(t)));
eq4=(pi*(L+uc(t))*(a1+wr1(t))^(2))*diff(p1(t))==(p1(t)-Bef)*((CD*Av*sqrt(2*(Bef-p1(t))*(p1(t)-p2(t))/(Bef*Rflu)))+pi*diff(uc(t))*(a2+wr1(t))^(2)+2*pi*(L+uc(t))*(a2+wr1(t))*diff(wr1(t)));
where uc,wr1,wr2,p1,p2 are state variables and mc,av Ft and t1 are fixed variables , all the other parameters are constant.
My problem is in the value of Ft=fo* sin(5000*t), for (t=0:0.63)sec then Ft=0 for (t=0.63:1)sec as a result for small increments I have 100 values of Ft and t1
I need to run my ode15s script 100 times for all 100 values of Ft and t1 then plot them in a single plot.
  댓글 수: 2
Jan
Jan 2017년 11월 13일
Okay. Then use loops to do this. Did you try this already? What exactly is the problem?
tamara hussien
tamara hussien 2017년 11월 13일
편집: Torsten 2017년 11월 13일
Thank you Mr.Jan Simon for asking about my problem. The problem occurs when I'm making a loop as follow:
t=0
fo=10
w=5000
for i=1:1:100
if (t<=0.63e-3)
f=fo*sin(w*t);
else
f=0;
end
T(i)=t;
Ft(i)=f
t=t+0.00001
end
now when I call my function handle as
Q = @(t, y) f(t, y, Ft, Av, mc)
y0est = [0; 0; 0; 0; 0; 0; 0; 0]; % initial values y0=[uc,wr1,wr2,p1,p2,uc",wr1",wr2"]
yp0est = zeros(8,1);
opt = odeset('Mass', M, 'InitialSlope', yp0est,...
'RelTol', 10.0^(-6), 'AbsTol' , 10.0^(-6));
implicitDAE = @(t,y,yp) M(t,y)*yp - Q(t,y);
[y0, yp0] = decic(implicitDAE, 0, y0est, [], yp0est, [], opt);
opt = odeset(opt, 'InitialSlope', yp0);
t1=0:1e-4:1e-3;
t2=t1+1e-6;
[tSol,ySol] = ode15s(Q, [t1 t2], y0, opt)
% y is vector of all state variables, t is time, Ft,Av,and mc are fixed variables.
here I can solve it for only one value of Ft and t1 when I'm writing it as Q(i)= @(t, y) f(t, y, Ft(i), Av, mc) the matlab gives me the error as "Dimensions of matrices being concatenated are not consistent." If possible please give me your email address, then I will attach to you my matlab code, because it is to much i can't write it here. Best regards

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답변 (1개)

Yogananda Jeppu
Yogananda Jeppu 2017년 11월 13일
Try a simple Euler integration. Xd = f(a,b,c ...). x = Xd*dt+x; store the values of x in an array. See if this works.
  댓글 수: 2
tamara hussien
tamara hussien 2017년 11월 14일
Thank you Mr Yogananda Jappu for your time. I already made a function handle for all variables but When I call back this fuction for n values of x as array, matlab returns to the error in the function handle” matrix dimensions must agree”
Steven Lord
Steven Lord 2017년 11월 14일
tamara hussien had flagged this answer as "Good idea".
The purpose of flagging in the MATLAB Answers help is:
"A flag is a request for review that any contributor can assign to content. Contributors with sufficient privileges can then review and potentially revise, close, or delete the flagged content.
Questions, answers, and comments can be flagged if unclear, not appropriate, or spam."
Since you seem happy with the suggestion, I'm going to remove the flag.

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