Example 4.  Consider the modified Joukowski airfoil when  [Graphics:Images/JoukowskiTransMod_gr_202.gif]  is used to map the Z plane onto the W plane.  Refer to Figure 11.69 and discuss why the angle of the trailing edge of the modified Joukowski airfoil [Graphics:Images/JoukowskiTransMod_gr_203.gif] forms an angle of [Graphics:Images/JoukowskiTransMod_gr_204.gif] radians.  

Figure 11.69  The images of the circles [Graphics:Images/JoukowskiTransMod_gr_205.gif] and [Graphics:Images/JoukowskiTransMod_gr_206.gif] under the modified Joukowski airfoil.

Solution 4.

    The image of the circle [Graphics:../Images/JoukowskiTransMod_gr_207.gif] is the line [Graphics:../Images/JoukowskiTransMod_gr_208.gif], then two rays [Graphics:../Images/JoukowskiTransMod_gr_209.gif] and [Graphics:../Images/JoukowskiTransMod_gr_210.gif], and then two arcs [Graphics:../Images/JoukowskiTransMod_gr_211.gif] and [Graphics:../Images/JoukowskiTransMod_gr_212.gif] in the respective Z,  W, and w planes.  The image of the circle [Graphics:../Images/JoukowskiTransMod_gr_213.gif] is the circle [Graphics:../Images/JoukowskiTransMod_gr_214.gif], then the "cardioid like" curve [Graphics:../Images/JoukowskiTransMod_gr_215.gif], and then the modified Joukowski airfoil [Graphics:../Images/JoukowskiTransMod_gr_216.gif].  The details are left as an exercise for the reader in the book.

Complex Analysis for Mathematics and Engineering

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) 2006 John H. Mathews, Russell W. Howell