Shooting Method Boundary Conditions not Implementing
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I am trying to implement RK4 using the shooting method for the following boundary layer equations,
n = 0.4;
Bo = 0.01322917839;
dy = zeros(5,1);
dy(1) = y(2);
dy(2) = ((2*n+1)*y(3)*y(2)*Bo^(2/(n+1))/(n+1))/0.2e1;
dy(3) = y(4);
dy(4) = y(5);
dy(5) = ((-y(4)^2*n+2*y(3)*y(5)*n+2*y(1)*n-y(4)^2+y(3)*y(5)+2*y(1))/y(5)^(n-1)/n/(n+1))/0.2e1;
Where,
y(1) = theta
y(2) = theta'
y(3) = f
y(4) = f'; and
y(5) = f''
Subject to the following Boundary Conditions,
3 initial conditions are given: eta=0, f(0)= f'(0)=0,theta(0)=1
The boundary conditions that needs to be satisfied are: f'(eta=inf)= 0 and theta(eta=inf)=0 as eta=30.
I have tried the following code but the graph I get is not as it's supposed to be.
function Shooting_Method_code1
clc
clear all
x = [0.5 0.5];
options = optimset('Display', 'iter');
x1 = fsolve(@solver,x);
end
function F = solver(x)
options = odeset ('RelTol', 1e-8, 'AbsTol', [1e-8 1e-8 1e-8 1e-8 1e-8]);
[t,u] = ode45(@equation, [0,1], [1 x(1) 0 0 x(2)], options);
s = length(t);
F = [u(s,1)-0, u(s,4)-0];
figure(1)
plot(t,u(:,1), t, u(:,4))
end
function dy = equation(t,y)
dy = zeros(5,1);
n = 0.4;
Bo = 0.01322917839;
dy = zeros(5,1);
dy(1) = y(2);
dy(2) = ((2*n+1)*y(3)*y(2)*Bo^(2/(n+1))/(n+1))/0.2e1;
dy(3) = y(4);
dy(4) = y(5);
dy(5) = ((-y(4)^2*n+2*y(3)*y(5)*n+2*y(1)*n-y(4)^2+y(3)*y(5)+2*y(1))/y(5)^(n-1)/n/(n+1))/0.2e1;
end
Please help.
댓글 수: 8
Mayokun Ojediran
2019년 7월 3일
Torsten
2019년 7월 3일
The boundary conditions seem to be satisfied for the solution you get.
Why do you write that the graph is not as it is supposed to be ?
Mayokun Ojediran
2019년 7월 3일
Torsten
2019년 7월 3일
Did you try bvp4c ?
Mayokun Ojediran
2019년 7월 3일
Torsten
2019년 7월 4일
function main
xmesh = linspace(0, 30, 1000);
solinit = bvpinit(xmesh, [0; 0; 0; 0; 0]);
sol = bvp4c(@equation, @bcfcn, solinit);
plot(sol.x,sol.y(4,:))
end
function dy = equation(t,y)
dy = zeros(5,1);
n = 0.4;
Bo = 0.01322917839;
dy = zeros(5,1);
dy(1) = y(2);
dy(2) = ((2*n+1)*y(3)*y(2)*Bo^(2/(n+1))/(n+1))/0.2e1;
dy(3) = y(4);
dy(4) = y(5);
dy(5) = ((-y(4)^2*n+2*y(3)*y(5)*n+2*y(1)*n-y(4)^2+y(3)*y(5)+2*y(1))/y(5)^(n-1)/n/(n+1))/0.2e1;
end
function res = bcfcn(ya,yb)
res(1) = ya(1)-1.0;
res(2) = ya(3);
res(3) = ya(4);
res(4) = yb(1);
res(5) = yb(4);
end
Mayokun Ojediran
2019년 7월 8일
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