Solving an ODE system with dsolve function

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Alessio Pricci
Alessio Pricci le 15 Oct 2022
Modifié(e) : Jan le 15 Oct 2022
Hi everyone,
I am trying to solve the following system of ODEs with the dsolve command:
syms h11(r) T11(r) f11(r)
R=1e-3;
Tw=500;
ode1=3508*exp(7463/2000 - T11(r)/100)*diff(f11(r), r)^(6/5) - (9*(r*diff(T11(r), r, r) + diff(T11(r), r)))/(50*r) == 0;
ode2=- (9*(r*diff(h11(r), r, r) + diff(h11(r), r)))/(50*r) - (877*exp(7463/2000 - T11(r)/100)*h11(r)*diff(f11(r), r)^(6/5))/25 == 0;
odes=[ode1;ode2];
cond1=f11(R)==0;
cond2=T11(R)==Tw;
cond3=h11(0)==0;
cond4=h11(R)==0;
cond5=subs(diff(h11,r),r,0)==0;
conds = [cond1; cond2; cond3; cond4; cond5];
dsolve(odes,conds);
I would like to find the unknowun function f11, T11 and h11 based on the previous ODE system, but the following error appears:
Expecting an ODE in the specified variable.
I would appreciate Your help in finding a solution for this problem.
Best regards,
AP
  3 commentaires
Alessio Pricci
Alessio Pricci le 15 Oct 2022
Thanks for your reply, Torsten.
I considered also this way, but I managed to solve only problems where there is a single ODE with its boundary conditions.
How to perform this for a system, as in this case?
Torsten
Torsten le 15 Oct 2022
Modifié(e) : Torsten le 15 Oct 2022
There are many examples in the documentation for systems.
Both examples under
are systems of two equations.
In your case, there would be 4 equations (T11, T11r, T11rr, f11)

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