How to find solution for Blasius Equation?

function blasius
xa = 0; xb = 7;
solinit = bvpinit(linspace(xa,xb,1000),[0 0 0]);
sol = bvp4c(@blasius_equation,@bc,solinit);
xint = linspace(xa,xb,1000);
Sxint = deval(sol,xint);
plot(xint,Sxint([2 2],:));
function res = bc(ya,yb)
res = [ ya(1); ya(2); yb(2)-1];
function dydx = blasius_equation(x,y)
dydx = [y(2); y(3); (-y(1)*y(3))/2];

I did not get the error. But if i change the line "plot(xint,Sxint([2 2],:));" to "plot(xint,Sxint([1 2],:));", i get two lines in the graph. What does this line in the program means?

[Geoff Hayes]

Aruna - what have you tried to verify that the equation is correct? Or, do you observe errors? Please discuss what you have written and why you think it may not be correct.

Also, see http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency

[Walter Roberson]

What is the question here? http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

Answer 1

[Torsten]

plot(xint,Sxint([2 2],:));

plots y(2) over [xa xb].

I don't know why you or the author of the code does not simply use

plot(xint,Sxint(2,:));

Best wishes

Torsten.

[Aruna P]

If xa and xb are not equal then how to use it? why do i get one line in a graph if i use

plot(xint,Sxint([2 2],:));

and two lines in a graph if i use

plot(xint,Sxint([1 2],:));

[Torsten]

Blasius equation reads y'''+0.5*y*y''=0.

plot(xint,Sxint([2 2],:));

only plots y' while

plot(xint,Sxint([1 2],:));

plots y and y'.

Best wishes

Torsten.

[Aruna P]

thank u

[Aruna P]

how could i get the values?

[Torsten]

http://de.mathworks.com/help/matlab/ref/fprintf.html

Best wishes

Torsten.

[Aruna P]

Sorry i could not understand. Could you help me?

[Aruna P]

i tried using "vpasolve" but i am getting error

[Torsten]

I don't understand what you are trying to do.

To print the results to a file, use fprintf after the command

plot(xint,Sxint([2 2],:));

Best wishes

Torsten.

Answer 2

[Maria Hamdani]

what will i do if i have to print table of f,f'and f'' for different values of eta

[Geoff Hayes]

Maria - please post your above question as a question rather than as an answer.