
[Sponsors] 
March 5, 2010, 01:40 
blasius equation

#1 
Member
varun
Join Date: Apr 2009
Posts: 35
Rep Power: 8 
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 

March 5, 2010, 02:16 

#2 
New Member
Join Date: Mar 2010
Posts: 2
Rep Power: 0 

March 5, 2010, 03:37 

#3 
Member
varun
Join Date: Apr 2009
Posts: 35
Rep Power: 8 
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. 

March 5, 2010, 13:11 

#4 
New Member
Join Date: Mar 2010
Posts: 2
Rep Power: 0 

March 5, 2010, 14:43 

#5 
Member
varun
Join Date: Apr 2009
Posts: 35
Rep Power: 8 
hey thanks a lot.... i really appreciate your help


March 5, 2010, 22:56 
There is a code for Blasius solution

#6 
Member
Join Date: Mar 2009
Posts: 33
Rep Power: 8 
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 

March 6, 2010, 03:35 

#7 
Member
varun
Join Date: Apr 2009
Posts: 35
Rep Power: 8 
hey, thanks, i did got what i wanted but this link is also very helpful.... thanks a lot


May 1, 2010, 15:07 
help me

#8 
New Member
shahrouz
Join Date: May 2010
Posts: 3
Rep Power: 7 
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 

May 1, 2010, 18:02 

#9 
Senior Member
Join Date: Nov 2009
Posts: 411
Rep Power: 11 
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 

May 2, 2010, 11:13 

#10 
Member
Join Date: Mar 2009
Posts: 33
Rep Power: 8 
>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 Last edited by gory; May 2, 2010 at 18:10. 

May 2, 2010, 12:32 

#11  
New Member
shahrouz
Join Date: May 2010
Posts: 3
Rep Power: 7 
Dear groy
http://www.cfdbooks/.com I couldn't find the book could u give me the name of it? Thanks alot! Quote:


May 2, 2010, 12:59 

#12 
New Member
shahrouz
Join Date: May 2010
Posts: 3
Rep Power: 7 
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 

May 2, 2010, 15:18 

#13 
New Member
vo
Join Date: May 2010
Posts: 1
Rep Power: 0 
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.


May 2, 2010, 18:15 

#14 
Member
Join Date: Mar 2009
Posts: 33
Rep Power: 8 
>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 

June 5, 2011, 12:37 

#15 
New Member
Udhab Adhikari
Join Date: May 2011
Posts: 2
Rep Power: 0 
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.


June 25, 2012, 09:42 
Vertical velocity of boundry layer over a horizontal flat plate

#16 
New Member
Mohsen Hashemzadeh
Join Date: Jun 2012
Location: Iran
Posts: 1
Rep Power: 0 
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?? 

Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Calculation of the Governing Equations  Mihail  CFX  7  September 7, 2014 06:27 
Viscosity and the Energy Equation  Rich  Main CFD Forum  0  December 16, 2009 15:01 
mass flow in is not equal to mass flow out  saii  CFX  2  September 18, 2009 08:07 
continuity equation  Rafal  Main CFD Forum  4  November 29, 2006 10:27 
Blasius equation.  Lawal  Main CFD Forum  7  November 15, 2004 15:45 