Making use of relations from Equations (322) and (324) such as 



9$. 



3$. , 9 2 $, 



-1 = I L 2 $.-2i03U -^ -U 2 — ri 



9z g I i 9x „ 2 



9x 



L / 2 * 3 *j 2 32 *j* 



J- = i ,,> rfi j-9-i,.»TT J- -TT — J- 



.10 $.+2i(0U -r- 1 - -U 

 9z g \ j 9x 3x 2 



and integrating by parts with respect to x, we obtain 



9z 9z j 



-it (•. 



J ( g \9x j i 



. J dxdy 



9x/ g , i j ' 



Therefore, we have 



icot r 

 F - e p q 



9$. 

 l dn 



icot r 

 = e p I 



J J, ] 3n J |g \9x j i 



2icoU * * 



z / g i J 



L s 



*. dy 



Now we put 



F.. = e iWt p g.T.. 



(327) 



(328) 



and write the force or moment when the uniform flow has an opposite 

 direction as 



P.? = e ±Wt pE.I.. 



(329) 



Then the following relation is valid. 



T. . = T. . + L. . 



(330) 



116 



