ODE coupled with classic equation
3 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
Hi everybody.
After some research can't found a solution..
I have 2 variable wich depend on time : E and W(E)
then I have an differential equation of rho inked to W so linked to E so linked to t.
Can I use E et W as vector inside the ODE declaration?
clc
clear all
close all
u=2.405;
c=3e8;
T0=100e-15;
lambda0=515e-9;
w0=2.*pi.*c./lambda0;
Ej=100e-6;
Pp=Ej./T0;
r=18e-6;
th=250e-9;
s=0.085;
dt=T0./1000;
t=-T0*5:dt:T0*5;
Fs=1./dt;
nn=length(t),
freq = Fs*linspace(0,(nn/2),(nn/2)+2)/nn+c/lambda0;
freq=fliplr(freq(1:end-1));
l=c./freq;
ll=-fliplr(l);
lll=ll-ll(1)+l(end);
lll = (circshift(lll',-1))';
lambda=[l lll];
lambda=lambda(1:end-1);
w=2.*pi.*c./lambda;
E=Pp.*exp(-(t./T0).^2).*cos(w0.*t);
% plot(t,E)
a=r.*( 1+ s.*(2*pi.*c).^2./ (w.*w.*r.*th) ).^(-1);
% plot(lambda,a)
a=9.9992e28;
b=3.5482e11;
rho0=2.7e26;
W=a./(abs(E)).*exp(-b./(abs(E)));
syms rho(t) EE(t) WW(t)% Y ;
ode1= EE== Pp.*exp(-(t./T0).^2).*cos(w0.*t);
ode2 = WW==a./(abs(EE)).*exp(-b./(abs(EE)))
ode3 = diff(rho,t) == W(t) .*(rho0 - rho);
ode=[ode1 ode2] ode3
rhoSol=solve(ode)
%%%or
yms rho(t) ;
ode = diff(rho,t) == W(t) .*(rho0-rho);
rhoSol=solve(ode)
If you have an idea to solve this?
Regards
MM
2 Commenti
Risposta accettata
darova
il 23 Ott 2019
Try this
E = @(t) E0*exp(-t^2/tau^2)*cos(w0*t);
w = @(t) a/E(t)*exp(-b/E(t));
rho = @(t,rho) w(t)*(rho-rho0);
[t,r] = ode45(rho,[0 0.1],1);
plot(t,r)
7 Commenti
darova
il 23 Ott 2019
- It's not r wich is drho/dt (the solution if their is)?
Yes. BUt if rho is inf or NaN drho/dt cannot be found. You asked why all r are NaN - this is the answer, because of rho
Più risposte (1)
Vedere anche
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!