I am trying to solve a system of ordinary differential equations using Bvp4c but I get a message error that a singular Jacobian encountered, below the code I am working on
2 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
test3()
function test3
clear
clc
close all
format long
%% ------------------------------------------------------------------------
% Parameters
%--------------------------------------------------------------------------
NP=100; %the number of meshpoints
eta_infty =15;
%% ------------------------------------------------------------------------
for i=1:5
A=[2 3 4 5 6];
gamma=A(i);
eps=0.001; %A=0.1*[2 4 6 8 9]; %Medium porosity
Beta=0.5; %A=0.1*[1 2 3 4 5]; %Beta casson parameter
Omega=7; %A=[4 5 6 7 8]; %cylinder curvature parameter
M=6; %A=[2 3 4 5 6]; %magnetic field parameter
P=5; %A=[3 4 5 6 7]; %porous medium parameter
Gr=0.2; %A=[0 2 3 4 5]; %themal Grashof number
Gm=0.3; %mass Grashof number
Alpha=20; %curvature angel
Pr=7.56; %for water7.56 %prentdl number
Rd=0; %A=0.1*[0 1 3 5 7]; %Radiation parameter
Ec=0.01; %Eckert number
Nt=0.3; %A=0.1*[1 2 3 4 5]; %thermophoresis parameter
Nb=0.2; %A=0.1*[2 3 4 5 6]; %Brownian motion parameter
Sc=5; %A=[5 7 9 11 13]; %Schmidt number
%gamma=3; %A=[2 3 4 5 6];
xi_1=0.001;
xi_2=0.001;
QM=0.01; %mass flux
QH=0.01; %heat flux
%--------------------------------------------------------------------------
%lamda=0.001; %A=[0.001 0.002 0.003 0.004 0.005];lamda parameter
%Pe=Re*Pr; % peclet number
%Re=0.001;
%A1=1/Pr;
%A2=1/Sc;
%--------------------------------------------------------------------------
% Solve the problem
%--------------------------------------------------------------------------
int=ones(1,7); %We have 7 variables
int=0.*int;
% int=[0 0 -0.003 -0.35 0 0 -0.05];
options = [];
solinit = bvpinit(linspace(0,eta_infty,NP),int);
sol = bvp4c(@fsode,@fsbc,solinit,options);
eta = sol.x; %this is eta
f = sol.y; %These are the dependenat variables
FF=f(1,:);
DF=f(2,:);
%DDF(i)=-f(3,1)
TH=f(4,:);
%DTH(i)=f(5,1);
Fi =f(6,:);
%QH=(1+xi_2)*gamma+(1/Pr)*(1+((4*Rd)/3))*DTH;
%% ------------------------------------------------------------------------
% Plot the results
% The model equations
%--------------------------------------------------------------------------
end
function dfdeta = fsode(eta,Y)
F(1) = Y(2);
F(2) = Y(3);
F(3) =(-eps*((1+(1/Beta))*(1+(2*Omega*eta))))*(((2*Omega*(1+(1/Beta))*Y(3))/eps)+(1/eps^2)*(Y(1)*Y(3)-(Y(2))^2)-(M+P)*Y(2)+(Gr*Y(4)-Gm*Y(6))*cosd(Alpha));
F(4)=Y(5);
F(5)=(-Pr/((1+(2*Omega*eta))*(1+((4/3)*Rd))))*(((2*Omega*(1+((4/3)*Rd))*Y(5))/Pr)+((1+(1/Beta))*(1+(2*Omega*eta))*Ec*(Y(3))^2)+((1+(2*Omega*eta))*((Nt*(Y(5))^2)-(Nb*Y(5)*Y(7))))+(M*Ec*(Y(2))^2)+(Y(1)*Y(5)));
F(6)=Y(7);
F(7)=(-1/(1+(2*Omega*eta)))*((2*Omega*Y(7))-((Nt/Nb)*(((1+(2*Omega*eta))*F(5))+(2*Omega*Y(5))))+(Sc*Y(1)*Y(7)));
dfdeta = [ F(1)
F(2)
F(3)
F(4)
F(5)
F(6)
F(7)
];
end
% --------------------------------------------------------------------------
function res = fsbc(ya,yb)
res = [ya(1)-gamma % f-gamma=0
ya(2) % f'=0
ya(4)-1 %TH=1
((Sc/eps)*(ya(6)-xi_1)*ya(1))+ya(7)+((Nt/Nb)*ya(5))-QM %Mass flux
yb(2) %f'=0
yb(7)-1 %phi=1
(((1+(2*Omega*eta_infty))^(-1/2))*(yb(4)+xi_2)*yb(1))+((1/Pr)*((1+(2*Omega*eta_infty))^(-1/2))*(1+((4/3)*Rd))*yb(5))-QH %Heat flux
];
end
end
2 Kommentare
Torsten
am 17 Jan. 2024
This error message usually appears if there is something wrong in the setup of your model equations and/or boundary conditions. So we cannot help in this case apart from saying: Recheck your model equations and boundary conditions and their implementation in the code.
Antworten (0)
Siehe auch
Kategorien
Mehr zu Neural Simulation 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!