Error solving Boundary value Problem using bv4pc function
2 views (last 30 days)
Show older comments
Hi, I am getting the following error while solving this BVP.
Error using bvp4c (line 251)
Unable to solve the collocation equations -- a singular Jacobian encountered.
Error in MaxwellYangHWDiff (line 33)
sol = bvp4c(@(r,y)odefun(r,y,phi,chi),@(ycent,ysurf)bcfun(ycent,ysurf,c1,c2,c3,c4),init);
My code is as follows:
clc
clear all
R = 0.04; % m Radius of the cylinder
f = 2800 * 10^6; % Hertz Frequency of microwave
c = 2.998 * 10^8; % m/s speed of light
mu_o = 1.257 * 10^-6; % Henry/m free space permeability
eps_o = 8.85 * 10^-12; % Frard/m free space permittivity
k1 = 42.6; % dielectric constant
k2 = 13.1; % dielectric loss
P_o = 250; % Watts
a_o = 2*pi*f/c; %free space wavenumber
E_o = sqrt(P_o*pi*a_o*R/(c*eps_o)); % V/m intensity of incident electric field
phi = R^2*(2*pi*f)^2*mu_o*eps_o*k1;
chi = R^2*(2*pi*f)^2*mu_o*eps_o*k2;
nt = 10; %number of nodes
dR = R/(nt-1); %increment
rstar = 0:(dR/R):(R/R);
c1 = R*a_o*((besselj(1,a_o*R)*besselj(0,a_o*R)+bessely(1,a_o*R)*bessely(0,a_o*R))/((besselj(0,a_o*R))^2+(bessely(0,a_o*R))^2));
c2 = 2/(pi*((besselj(0,a_o*R))^2+(bessely(0,a_o*R))^2));
c3 = -(4/pi)*bessely(0,a_o*R)/((besselj(0,a_o*R))^2+(bessely(0,a_o*R))^2);
c4 = -(4/pi)*besselj(0,a_o*R)/((besselj(0,a_o*R))^2+(bessely(0,a_o*R))^2);
init = bvpinit(linspace(0,0.04,10),[0 0 0 0]);
sol = bvp4c(@(r,y)odefun(r,y,phi,chi),@(ycent,ysurf)bcfun(ycent,ysurf,c1,c2,c3,c4),init);
x = linspace(0,0.04,100); BS=deval(sol,x);
plot(x,BS(1,:))
function dydr = odefun(r,y,phi,chi)
dydr=zeros(4,1);
dydr(2)= -((1/r)*y(2)+phi*y(1)-chi*y(3));
dydr(4)= -((1/r)*y(4)+phi*y(3)-chi*y(1));
end
function res = bcfun(ycent,ysurf,c1,c2,c3,c4)
res =[ycent(2); ycent(4); ysurf(2)+c1*ysurf(1)+c2*ysurf(3)-c3; ysurf(4)+c1*ysurf(3)-c2*ysurf(1)-c4];
end
0 Comments
Accepted Answer
darova
on 12 Jan 2020
Try r = 1e-3
I think you forgot about dydr(1) and dydr(3)
function dydr = odefun(r,y,phi,chi)
dydr=zeros(4,1);
% dydr(1) = y(2);
dydr(2)= -((1/r)*y(2)+phi*y(1)-chi*y(3));
% dydr(3) = y(4);
dydr(4)= -((1/r)*y(4)+phi*y(3)-chi*y(1));
end
More Answers (0)
See Also
Categories
Find more on Boundary Value Problems in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!