# hw9 - the location of the max camber What tells you the...

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AAE333 Fall 2009 Problem Set #9 Due: Monday 11/09/9 10% bonus if turned in on Friday 11/6/9 You are going to find the incompressible potential flow over an NACA 2414 airfoil at angle of attack using the source/vortex panel method described in class. There are two matlab files you will need. First is the same as you used for HW8 : function [U,V]=velfrompanel(x1,y1,x2,y2,xc,yc) calculates the x & y velocity components (U,V) at a specified point (xc,yc) induced by a unit strength source sheet connecting specified points (x1,y1) and (x2,y2). (or, equivalently, the velocities induced by a uniform strength vortex sheet) The second is an example for a different airfoil: airfoil_examp.m (posted in the HW9 folder) Before doing anything for the NACA2414 airfoil, make sure you can run the example, varying the angle of attack and the thickness/chord ratio. a) Consider the NACAabcd (“4 digit series”) airfoils. What is the meaning of the four digits: abcd? Specifically, what tells you the thickness/chord ratio? What tells you
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Unformatted text preview: the location of the max camber? What tells you the value of the max camber? What are the values of these quantities for the 2414? b) The geometry of the NACA 4 series is coded in the Matlab function naca4.m, available in the HW9 directory. (The formulas coded there are from Abbott & von Doenhoff). The basic shape has a “chopped off” trailing edge. What is the thickness of that TE (in units of the chord length)? Why is it chopped? c) The naca4 function has a closure option, which removes the chopped off TE by slightly altering the aft of the airfoil to a point. Compare the open and closed shapes… especially near the TE. d) Calculate the pressure distribution on the NACA2414 at 10deg aoa, using both the “open” and “closed” shapes. Examine the pressure distribution near the TE in particular. What’s the difference? e) Calculate the lift coefficient by using the Kutta-Joukowski law. Also calculate it by direct integration of the pressure. Do you get the same answer?...
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