How do I get the second solution?
Show older comments
function Shrink;
format short
global lambda Pr
Pr = 1; %fixed
a = 0;
b = 10; % b = infinity
lambda =-1.1; %mixed convection parameter (lambda)
solinit = bvpinit(linspace(a,b,100),@Shrink_init);
options = bvpset('stats','on','RelTol',1e-10);
sol = bvp4c(@Shrink_ode,@Shrink_bc,solinit,options);
figure(1)
plot(sol.x,sol.y(2,:),'k--','linewidth',1)
xlabel('\eta','fontsize',16)
ylabel('f\prime(\eta)','fontsize',16)
hold on
figure(2)
plot(sol.x,sol.y(4,:),'k--','linewidth',1)
xlabel('\eta','fontsize',16)
ylabel('\theta(\eta)','fontsize',16)
hold on
sol.y(3,1) % The value of f''(0)
-sol.y(5,1) % The value of -theta'(0)
descris = [sol.x; sol.y];
save ('start_main.mat', '-struct', 'sol');
function dydx = Shrink_ode(x,y,Pr,lambda);
global Pr lambda
dydx = [y(2)
y(3)
y(2)^2-y(1)*y(3)-1-lambda*y(4)
y(5)
-Pr*y(1)*y(5)+Pr*y(2)*y(4)];
function res = Shrink_bc(ya,yb);
res = [ya(1)
ya(2)
yb(2)-1
ya(4)-1
yb(4)];
function v = Shrink_init(x);
v =[];???????????????
1 Comment
Jan
on 25 Oct 2022
The question is not clear. Please take the time to explain any details.
Answers (1)
Pr = 1; %fixed
lambda =-1.1; %mixed convection parameter (lambda)
a = 0;
b = 10; % b = infinity
solinit = bvpinit(linspace(a,b,100),@Shrink_init);
options = bvpset('stats','on','RelTol',1e-10);
sol = bvp4c(@(x,y)Shrink_ode(x,y,Pr,lambda),@Shrink_bc,solinit,options);
figure(1)
plot(sol.x,sol.y(2,:),'k--','linewidth',1)
xlabel('\eta','fontsize',16)
ylabel('f\prime(\eta)','fontsize',16)
figure(2)
plot(sol.x,sol.y(4,:),'k--','linewidth',1)
xlabel('\eta','fontsize',16)
ylabel('\theta(\eta)','fontsize',16)
%hold on
sol.y(3,1) % The value of f''(0)
-sol.y(5,1) % The value of -theta'(0)
%descris = [sol.x; sol.y];
%save ('start_main.mat', '-struct', 'sol');
function dydx = Shrink_ode(x,y,Pr,lambda);
dydx = [y(2)
y(3)
y(2)^2-y(1)*y(3)-1-lambda*y(4)
y(5)
-Pr*y(1)*y(5)+Pr*y(2)*y(4)];
end
function res = Shrink_bc(ya,yb);
res = [ya(1)
ya(2)
yb(2)-1
ya(4)-1
yb(4)];
end
function v = Shrink_init(x);
v =[0 1 0 1 1];
end
2 Comments
MOSLI KARIM
on 1 Apr 2023
Hi Mr. Torsten, I have a question, why did you choose the initial conditions
function v = Shrink_init(x);
v =[0 1 0 1 1];
end
Torsten
on 2 Apr 2023
I took one of the boundary conditions as initial value for the complete region of integration.
Somewhat arbitrary - but often it works.
Categories
Find more on Programming 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!
