# Displacement and momentum thickness around Naca 0012 in a Transonic Flow

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 June 22, 2013, 12:32 Displacement and momentum thickness around Naca 0012 in a Transonic Flow #1 New Member   Mohammad Sobhani Join Date: Sep 2012 Location: Iran, Tehran Posts: 8 Rep Power: 13 Hi everybody ! I'm simulating flow around a Naca 0012 airfoil with angle of attack 1.25 (degree) and farfield mach number 0.8. The results for displacement thickness and momentum thickness are shown in 2 graphs in following links. http://inspic.com/4412C0D6 http://inspic.com/42B9FFCD In all field, both of thickness are negative. Are they correct ?

 June 23, 2013, 05:28 #2 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,552 Blog Entries: 6 Rep Power: 53 how did you calculate momentum and displacement thickness?

 June 23, 2013, 08:43 #3 New Member   Mohammad Sobhani Join Date: Sep 2012 Location: Iran, Tehran Posts: 8 Rep Power: 13 I've created some lines normal to airfoil and then export x-velocity & y-velocity on them. After that with a matlab code, I projected x-velocity & y-velocity on 2 directions: parallel to surface and normal to surface in each point. finally with an integration, i calculated displacements. displacement thickness = int[ 1 - rho * u / rho_inf / u_inf, 0 , inf ] momentum thickness = int[ rho/rho_inf * u / u_inf *( 1 - u/ u_inf), 0 , inf ] mm.abdollahzadeh likes this.

 May 6, 2014, 17:43 #4 New Member   Abhi Join Date: Feb 2014 Posts: 8 Rep Power: 12 Hi, Your post is very interesting. I am working on a similar 3D problem and having hard time in getting MOmentum and displacement thickness. I appreciate if you can post the matlab script. I know hoe to create lines and get x and y velocity data from Fluent. Thanks

 Tags displacement thickness, fluent, momentum thickness, naca 0012, transonid