blasius equation

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 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: 10 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:
 Originally Posted by gory >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

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

Quote:
 Originally Posted by DoHander 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, 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??

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