[scilab-Users] problem with scilab

[CRETE Denis]

Hello,
I changed g/R to gsR and deltaP/B  to deltaPsB=1. Attempts with gsR=1 ...10 are solved correctly by Scilab. An oscillatory behaviour is found for g/R=10, and perhaps for g/R > deltaP/B (?).
Denis

De : arnaud dujeu [mailto:fangorn813 at hotmail.com]
Envoyé : jeudi 21 juillet 2011 11:26
À : users at lists.scilab.org
Objet : [scilab-Users] problem with scilab

Hi,

I've got a problem to solve a non linear differential equation, which is :

y1'=A*(1-sin(y2))/(pi/2-y2)-B*y1^2
y2'=y1


I'm using ode :


function [Xprime]=VanDerPol(t, X)



 Xprime(1) = X(2)

 Xprime(2) = g/R*(1-sin(X(1)))/(%pi/2-X(1))-deltaP/(B*(%pi/2-X(1)))



endfunction



 t=linspace(0,4,3000); X0=[85*%pi/180;0];

 [u]=ode(X0,0,t,VanDerPol);



plot(t,u(1,:)*180/%pi,'r')

 plot(t,R*u(2,:))





but it doesn't work.



Do you know why?



Best regards.
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