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-   -   blasius equation (http://www.cfd-online.com/Forums/main/73342-blasius-equation.html)

varunjain89 March 5, 2010 01:40

blasius equation
 
hello....

i have written code for boundary layer eqns over flat plate, and its working fine.

now i need to compare my results with blasius solution, so where or how can i get the data for analytical blasius solution.

thanks in advance
varun

pricegr March 5, 2010 02:16

http://www.imc.pcz.czest.pl/instytut...bl/afm_bl7.pdf

varunjain89 March 5, 2010 03:37

i don't get it....
look my free stream velocity is 100,
pressure and density are sea level value...

i need to plot boundary layer profile @ different values of x...

or basically i need to calculate f' @ different values of x along the flat plate... so how can i calculate f'....

isn't there any site where i can directly get the data files, or data.

pricegr March 5, 2010 13:11

http://www.engr.sjsu.edu/nikos/cours...20solution.htm

varunjain89 March 5, 2010 14:43

hey thanks a lot.... i really appreciate your help :)

gory March 5, 2010 22:56

There is a code for Blasius solution
 
This may be what you want.

You can download a code that computes the Blasius solution (u,v,f,f',f'') at a 'given' point in the domain:
http://www.ossanworld.com/cfdbooks/cfdcodes.html

Good luck.
gory

varunjain89 March 6, 2010 03:35

hey, thanks, i did got what i wanted but this link is also very helpful.... thanks a lot :)

shahrouzalimo May 1, 2010 15:07

help me
 
Dear Sir.
I wrote a Matlab code for solving Blasius eq( f'''+0.5f*f''=0 ,f(0)=f'(0)=0,f'(inf)=1 )
1. I cannot write a function state , Matlab errors me y hasn't defined!?

2. how we replace f''(0)=0.322 instead of f'(inf)=1 ?


Can u help me ?
pls:(

DoHander May 1, 2010 18:02

In order to solve Blasius in Matlab you need to discretize your solution with a Finite Differences formula, or to write the equation as a system of 3 ordinary differential equations and use one of the ODE solvers available in Matlab.

Do

gory May 2, 2010 11:13

>2. how we replace f''(0)=0.322 instead of f'(inf)=1 ?


The trick is described in this book -> http://www.cfdbooks.com

Anyway, use f''(0)=0.3320573362151946, and solve the system of ODE.

Good luck.
gory

shahrouzalimo May 2, 2010 12:32

Dear groy
http://www.cfdbooks/.com I couldn't find the book could u give me the name of it?

Thanks alot!

Quote:

Originally Posted by gory (Post 257202)
>2. how we replace f''(0)=0.322 instead of f'(inf)=1 ?


The trick is described in this book -> http://www.cfdbooks/.com

Anyway, use f''(0)=0.3320573362151946, and solve the system of ODE.

Good luck.
gory


shahrouzalimo May 2, 2010 12:59

Dear DoHander

Have u write the code?
How can I write 3 ordinary differential equation?
I've written this code :

function dy = state(t,y)
dy = zeros(3,1); % a column vector
dy(1) = y(2);
dy(2) = y(3);
dy(3)=-0.5*y(1)*y(3);

but MatLab says that u have to input y ?


Best regards

Quote:

Originally Posted by DoHander (Post 257145)
In order to solve Blasius in Matlab you need to discretize your solution with a Finite Differences formula, or to write the equation as a system of 3 ordinary differential equations and use one of the ODE solvers available in Matlab.

Do


vo2 May 2, 2010 15:18

I am so glad for website like this. i have almost same problem and i make google search and find this website. thank you so much for making this available. i now save many time sent. :)

gory May 2, 2010 18:15

>I couldn't find the book could u give me the name of it?

Sorry, the link was in error. Try this one.
http://www.ossanworld.com/cfdbooks/cfdbooks.html

It's a book called "I do like CFD, VOL.1" which I personaly find very useful.

Or you can use or consult the code posted on that website,
which is this:
http://www.ossanworld.com/cfdbooks/c...blasius_v1.f90

Regards,
gory

udhab619 June 5, 2011 12:37

i need a c code for blasius solution over a flat plate. if anybody of u have it or know the link plz let me know.

mohsen.hashemzadeh June 25, 2012 09:42

Vertical velocity of boundry layer over a horizontal flat plate
 
Hello.
I wrote a code for blasius equation(2f'''+ff''=0) and i got the answers.
I want to find vertical velocity(v),but the velocity profile of v did not match with what really happen,Because out of boundary layer,there should be v=0,but using solution of Blasius Equation,v is inequal to 0.
How could I solve this problem??


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