Unable to meet the tolerance without using more than 1666 mesh points.
4 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Syed Mohiuddin
am 10 Jan. 2023
Kommentiert: Torsten
am 11 Jan. 2023
I have a coupled non-linear differential equations
(d^2 f)/(dy^2 )+m2*g2*dB/dy-2*i*R2*g1*f - g3*G1*y - R4*g1 = 0
(d^2 B)/(dy^2 )+t4/(1-i*H1)*df/dy=0
(d^2 T)/(dy^2 )-1/2*g4*G1*PR*(f+ ̅f)+ER*PR*[g5*(df/dy*d ̅f/dy)+g6*m2*(dB/dy*dB̅/dy)]=0, where ̅f is conjugate of f and B̅ is conjugate of B
Boundary conditions are
f=0 at y=0
f=C1 at y=1
And
dB/dy-(t4/(P1* (1-i*H1 ) ))* B=0 at y=0
dB/dy+(t4/(P2 (1-i*H1 ) ))* B=0 at y=1
and
T=0 at y=0
T=1 at y=1
I already got the solutions and graph for the first two equations with the help received from Torsen, but now i have extended the problem for three equations, when i run the program, i get an error "Unable to meet the tolerance without using more than 1666 mesh points", I tried using NMax but could not get the solution
Matlab programs
close all
clc
p=0.1;
P1=2;
P2=2;
b1=0.00021;
b2=0.000058;
S1=0.005;
S2=580000;
G1=2;
m2=20;
R1=997.1;
R2=3;
C1=0;
R3=4420;
H1=0.25;
K1=3;
R4=1;
PR=7.0;
ER= 2.0;
cf=4179;
cs=0.56;
K2=0.613;
K3=7.2;
t1=(1./((1-p).^2.5));
t2=(1-p)+(p.*(R3./R1));
t3=(1-p)+p.*((R3.*b2)./(R1.*b1));
S=(S2./S1);
t4=1-((3*(1-S).*p)./((2+S)+(1-S).*p));
t5=(1-p)+(p.*R3.*cs)./(R1.*cf);
t6=(1+2.*(K2./K3)+2.*p.*(1-K2./K3))./(1+2.*(K2./K3)-p.*(1-K2./K3));
g1=t2./t1;
g2=1/t1;
g3=t3./t1;
g4=t5./t6;
g5=t1./t6;
g6=1./(t4.*t6);
m1=(t4./(P1.*(1-1i.*H1)));
m2=(t4./(P2.*(1-1i.*H1)));
dydx=@(x,y)[y(4);
y(5);
y(6);
-m2.*g2.*y(4)+2.*1i.*R2.*g1.*y(1)+g3.*G1.*x+R4.*g1;
(-t4./(1-1i.*H1)).*y(3);
1/2.*g4.*G1.*PR.*(y(1)+conj(y(1)))-ER.*PR.*(g5.*(y(4).*conj(y(4))+g6.*m2.*(y(5).*conj(y(5)))))];
BC = @(ya,yb)[ya(1)-0;yb(1)-C1;ya(3)-0;yb(3)-1.0;ya(5)-m1.*ya(2);yb(5)+m2.*yb(2)];
yinit = [0.01;0.01;0.01;0.01;0.01;0.01];
solinit = bvpinit(linspace(0,1,50),yinit);
% options = bvpset('AbsTol',1e-6,'RelTol',1e-4,'stats','on','Nmax',1000);
options = bvpset('AbsTol',1e-6);
% options = bvpset('RelTol',1e-4);
%options = bvpset('stats','on');
%options = bvpset('Nmax',1000);
U1 = bvp4c(dydx,BC,solinit,options);
hold on
plot(U1.x,real(U1.y(3,:)),'b','linewidth',1.5)
plot(U1.x,imag(U1.y(3,:)),'r','linewidth',1.5)
5 Kommentare
Akzeptierte Antwort
Weitere Antworten (0)
Siehe auch
Kategorien
Mehr zu Graphics Performance finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!