# Blasius numerical solution?

1. Apr 18, 2004

### Clausius2

I have been doing a simulation of Blasius equation:

F'''+FF''/2=0 with F(eta) where eta is a similarity variable
eta=(y-1)/(x^(1/2))

F'(0)=1 u(y=1,x<<1)=1
F(0)=0 v(y=1,x<<1)=0
F'(infinite)=0 u(y=infinite, x<<1)=0

You can observe that the BC's are different of the flow over flat plate. This is obtained for a mixing thickness in the near field of a two-dimensional jet, near the orifice of exhaust (are you agree?).

http://www.rit.edu/~pnveme/Matlab_Course/Matlab_App_ODE.html [Broken]
where shooting method is employed in Matlab, it is said numerical methods (Runge Kutta, or the internal Matlab function ODE45) have normalized value F'(infinity)=1.

I have programmed it in Matlab but now I don't know how consider the value 0 at infinity instead of 1.
Could you help me?.
Thanks.

Last edited by a moderator: May 1, 2017
2. Apr 19, 2004

### Max0526

particular solution

Hi, Clausius2;
It seems to me, I was wrong in my private message to you about the almightiness of SMM. The only solution that classic SMM can give us is:
F(eta)=6/(eta+C),
where C is an arbitrary constant.
Max.

3. Apr 19, 2004

### Clausius2

I have used the superposition principle:

F(0)=0 F(0)=0 F(0)=0
F'(0)=1 F'(0)=1 F'(0)=0
F'(inf)=0 F'(inf)=2 F'(inf)=2
= -

Hey, it seems it works!, and I did't need your help.

But now, guys, you have to tell me if superposition principle is valid for this equation. Is it linear?. Hands up if you are agree!

4. Dec 6, 2011

### stichini2000

hello...... I am in a real bind here. i tried runnning numerous scripts but they dont work... the programme should include runge kutta
ps: Need help pronto!!!!
i would truely appreciate it