ode 45 and for loop

Hi,

I would like to use a for loop for a constant value i in my diff.eq. but I don't know how to implement it. Also I would like to have the matrices X and T for al the values of i.

for i : 0.1:0.1:10
    [T,X] = ode45(@fx, [0 4], [0 0]) %Can I implement i here and give the matrices X and T an index?
end

function dx = fx(t,x) % Can I give i as an input here.
     rho = 1.225;
     C_w = 0.3; 
     A = 0.005; 
     m = 0.314; 
     C_r = 0.035; 
     R_T = 0.7;
     n_0 = 378.33;
     i = 1;
     T_stall = 0.1868;
     r = 0.030;
     
     dx = zeros (2,1); 
     dx(1) = x(2);
     dx(2) = (-T_stall * R_T * i^2 * ((1000 * x(2)/ pi ) - n_0/i)/(n_0 * r) - m * 9.81 * C_r - 0.5 * rho * A * C_w * x(2)^2)/m;
     % the diff. eq. with i
end

Answer 1

[Stephan]

k = 0;
T_sol = cell(1,100);
X_sol = cell(1,100);

for ii = 0.1:0.1:10
    k = k+1;
    [T,X] = ode45(@(t,x)fx(t,x,ii), [0 4], [0 0]);
    T_sol{k} = T;
    X_sol{k} = X;
end

% plot first and last solution
plot(T_sol{1}, X_sol{1})
hold on
plot(T_sol{100}, X_sol{100})
hold off

function dx = fx(~,x,ii) % Can I give i as an input here.
     rho = 1.225;
     C_w = 0.3; 
     A = 0.005; 
     m = 0.314; 
     C_r = 0.035; 
     R_T = 0.7;
     n_0 = 378.33;
     T_stall = 0.1868;
     r = 0.030;
     
     dx = zeros (2,1); 
     dx(1) = x(2);
     dx(2) = (-T_stall * R_T * ii.^2 * ((1000 * x(2)/ pi ) - n_0/ii)/(n_0 * r) - m * 9.81 * C_r - 0.5 * rho * A * C_w * x(2)^2)/m;
     % the diff. eq. with i
end

[Tuur Vanderhaegen]

Thanks a lot!